and the manhunt for a murderer not going according to plan. dense terrain and brutal heat as police struggle with the search now in its eighth day and new questions about how the killer got away and how another prisoner did pretty much the same thing just a few months ago. police expected to update the situation this afternoon. we'll bring you that when it happens. plus, democrats, you have a problem. new poll numbers painting a bleak picture for president biden's re-election campaign. concerns about his age, his job performance, and new numbers showing one republican with the best chance to beat him. can you guess who it is? we're following these developing stories and many more all coming in right here to "cnn news central." rescuers in turkey are rushing to save an american trapped deep inside a cave. mark dickey is more than 3,000 feet below the earth's surface. 300 stories. the 40-year-old is an experienced caving instructor who was part of a research team in the morca valley, the third deepest cave in turkey. the hungarian cave rescue service says dickey suffered gastrointestinal bleeding and now needs to be carried out of that cave on a stretcher. officials say the rescue operation could take days. cnn's eleni giokos is following the story for us today. i wonder, deep underground here. do we know the status of the rescue at this point? >> yeah, i mean, look, it's ongoing. but i want you to picture this. a logistical and technical challenge 3,300 feet below the surface. in a cave where you've got narrow passages, very difficult terrain to navigate. for a very experienced caver it would take on a good day 15 hours to get to the surface. let's take you back to when mark dickey fell ill. six days ago he suffered gastrointestinal bleeding. he's received six units of blood. so this already has been on the go a few days now. 150 rescuers are currently there to try and assist, including rescue teams from the united states. overall we're seeing the message incoming using a stretcher is an option. but again, that is very difficult. it's very tricky and absolutely complex. he's currently stable. he's able to walk on his own. but if you know anything about caving, you need to be physically and mentally ready for such a huge journey out of the ground. even though with that kind of experience, he's been caving for over 20 years, his medical condition is not one that will allow him to get to the surface without this kind of assistance. overall i want you to imagine this. the empire state building. i want you to times that by three. that is how deep he is underground. there are various base camps under the surface, and we know that he's at one of the base camps right now. and in fact, in terms of commun commun communications, jim, they have to go close to the surface to communicate with people above the ground to get rigging assistance, technical teams, medical assistance, to try to figure out the best way forward. this could take days. >> eleni, do we know what exactly he was doing down there, what kind of research he was conducting? >> yeah, he was co-leading a team of researchers. and he usually does this around the world. he was trying to find a new route under this cave. now, you've got to remember, this is the third deepest cave in turkey. it's a hot spot for cavers to try and figure out terrain. and generally, this kind of research is important in understanding the dynamics of caves. that's all we know right now in terms of what he was trying to do. but he was with very experienced cavers. this was very meticulously planned. and of course someone like him with this kind of experience falling ill is absolutely the scariest, worst case scenario that could be occurring. the good thing is here, jim, that he knows exactly what he's in for in terms of trying to get out of this cave. >> 3,300 feet. it's not a straight line on the way up. eleni giokos, thanks so much. boris. >> we want to now introduce you to someone who knows mark dickey. emar mirza is an instructor for the national cave rescue mission. he's also an editor for the manual of u.s. cave rescue techniques. thanks so much for sharing part of your afternoon with us. we're sorry your friend is caught in this situation. what can you tell us about this care and the challenges now getting out of it? >> so obviously, he's very deep down in the cave. 1,000 meters, or 3,300 feet doesn't sound like it's that far in, except that that's going mostly straight down over a series of pitches where you have to have very highly technical rope skills. it's similar to climbing el capitan times two or three times. plus there's the horizontal caving that you have to do that's very tight over rugged terrain. you're crawling through hundreds and hundreds of feet of places where your chest and back -- it's extremely tight. physically demanding. and it's wet and cold. >> yeah, i can imagine. you were describing the conditions inside the cave. it obviously doesn't help matters that he has fallen ill. are you in communication with anyone on the ground there as far as his status is concerned now? >> not directly. they had very limited cell service basically until a little bit ago they did not have any cell service out in that area. but the national coordinator, the current national coordinator, gretchen baker, is involved with daily conference calls with some of the rescuers who are on site. >> anmar, i know that he was there on a research mission but i'm wondering what is it that drives someone so deep into the ground into such treacherous conditions? >> well, it's a combination of factors. obviously, there's the physical and mental challenge of it. you're doing something that very few people can do. but it's also these deep caves like this, they have unique microorganisms in them. they have unique features in them. finding out where the water path goes through the mountain is valuable. and then there's the element of competition of what is the deepest cave. currently the deepest cave in the world is over 2,200 meters deep. so finding the deepest cave in your country and pushing those to those greater and greater depths carries a lot of prestige -- within the community. in addition to the valuable information we get back from the research. >> yeah, it really is a fascinating field and such an interesting and demanding hobby or craft. how would this sort of rescue compared to some of the other famous wurngsz i'm thinking of the thai football team that was trapped in a cave a few years ago, or chilean miners as well? >> from the standpoint of difficulty, the physical difficulty in this cave would match similar to something like the thai rescue with the exception that the thai rescue was diving versus your open air caving. something along the lines of the chilean mine rescue, that's actually a very different situation because all of the activity, especially in the early part of the rescue, was happening out on the surface and where they were trying to drill in to find them. so in this case the bulk of the actual rescue activity as far as evacuating mark out is going to be happening underground where the aboveground folks are supporting that effort to the best that they can. they're especially doing that with very limited information. >> anmar mirza, we appreciate your perspective. we hope you get to chat with your friend mark very soon. >> thank you. >> of course. brianna? eight days, at least five sightings, four schools closed, and still a killer is on the run in pennsylvania and has stayed a step ahead of authorities. investigators say a resident spotted danelo cavalcante in a creek bed on tuesday about 2 1/2 miles from the chester county prison he escaped from a week ago today. yesterday authorities released security footage detailing just how the five-foot-tall murderer used his legs and arms to crab walk up two walls in the exercise yard and reach the roof and then push past razor wire to escape. people in the area are understandably nervous about having such a violent krim on the loose. he is serving time for stabbing his girlfriend 38 times, killing her in front of her young children. >> especially for a person to be on the loose for so long and it's so hot and you would think he would surface. he's got to have some skill set i guess in hiding. but hopefully he gets found too. >> cnn's danny freeman is in westchester, pennsylvania which is near the prison for us. so danny, you're hearing from the murder victim's sister. what can you tell us? >> reporter: that's right, brianna. we had a chance to speak with the sister of debra brandao. that is the woman who was brutally murdered by danelo cavalcante back in 2021. and that's really how this all started. that was the crime that landed cavalcante in the chester county prison behind me. i'll get to some of that sound in a moment. but brianna, i want to start here with just describing some of that truly stunning video that we first got about 24 hours ago. because it's worth mentioning exactly how this escape happened. it's been one of the big questions. and as you can see, this video released by local law enforcement. cavalcante put his hands up one wall, his legs up against the other and crab-walked all the way up to the roof. and brianna, it didn't stop there. law enforcement officials say he ran across the roof, he pushed through multiple layers of barbed wire and that was ultimately how he was able to escape. another note, brianna, is law enforcement said the tower guard did not see or report the escape at the time and that's potentially why cavalcante had an hour almost of a head start once he left the prison grounds. brianna, another important note to mention here is four months ago, back in may, there was another prison escape that law enforcement officials say basically mirrored the one that happened just last week. prison officials say they took steps to try and prevent future escapes after that may escape, but obviously that did not work. now, i want to get to that sound from the sister of debra brandao because it just showcases not only the fear that's generally in this community but the fear from, again, the family of the victim who was at the center of this cavalcante case. >> desperate. desperate. very scared. i thought about my children, obviously. i haven't slept for many days. since then i have been waking up with fright at night. i nap and wake up with fright. >> reporter: so again, you can hear right there, brianna, a lot of fear as this manhunt enters day eight. so the big question is where is cavalcante? police are still searching the area. the area that they're searching keeps expanding as well. we were driving around recently and we did see a police helicopter flying pretty low to the east of longwood gardens. it's a botanical garden nearby we were talking about earlier in the week. we have a press conference, brianna, coming up at 3:00 p.m. with local law enforcement. we plan to ask about that police activity and any recent sightings or clues to help capture this escaped inmate. brianna. >> we'll be staying tuned for that. danny, thank you for the very latest there. jim? >> let's speak to lenny depaul. he's a former commander for the u.s. marshal's service. lenny, good to have you here. as you know, the last sighting about 2 1/2 miles from the chester county prison. what level of confidence do you have that the authorities know the area he's currently in? is it possible he's outside that area? >> anything's possible. and good afternoon, jim. it speaks volumes that once he got out of the prison he didn't go far in the past eight days. i mean, two miles. the perimeter that's set up, they're pretty confident that he's still inside. human instincts have turned into animal instincts. desperate people do desperate things. he's breaking into homes now. he's tired. i'm sure he's sleeping with one eye open. it's 95 degrees. the bugs are biting. it's tough. from what i understand. and speaking to a couple of guys that are down range, it's a thick terrain. it's tough to get over. he's five foot -- i think he's five foot, 120 pounds. apparently he's -- sometimes it's better to be lucky than good. >> you mentioned the extreme heat, and it's record-breaking heat in the northeast right now. how would that specifically complicate the search for authorities, and how would it -- as you mentioned, it makes it difficult for the escapee as well. >> well, he hit the ground running. it's a force multiplier. they've got the u.s. marshal's service there. they're the best in the business at finding people. it's going to affect like canines. bloodhounds. they do the appropriate assets in place. aviation support. the drones are flying and whatnot, which is not affected by heat. but you know, the dogs, i know that's an issue. they're valuable. but if it's 95 degrees, they're limited as well. and as well as the men and women that are down range trying to find this guy. they're vested up. they're wearing -- in full battle regalia, if you will, boots and whatnot. it's a little difficult. i think it's a matter of time. the big question is, jim, what's his mindset? once that noose starts tightening and that perimeter, they get a bead on this guy, is it suicide by cop? does he throw his hands up? does he get into a house and is it a barricaded house or hostage situation? you have to act appropriately and hopefully this thing gets put to bed without incident, jim. >> no question. dangers lurk. let me ask you this, just looking back for a moment. because when you look at this video, we can call it up again, of him at first crabwalking his way up the wall of one entry way. but then he was able to make his way through i believe two sets of barbed wire. and this particular prison had an escape a number of weeks before. what does that tell you about the security in this prison? >> well, the warden's got some work to do. yeah-i think a month or so ago the other escapee pretty much mirrored like you said earlier, you know, what he did. so were they in conversation? he's back in custody. i don't think he was out there more than an hour. but i'm hoping somebody had a conversation with him to see if in fact he talked to this guy. they've got some work to do in the prison. he did get out. he was out there for a little while before they even recognized he was gone. it's an intense manhunt right now. and like i said, it's a full court press. hopefully this will end, you know, peacefully. >> yeah, that delay you mentioned gave him time to move, put some distance between himself and the prison. lenny depaul, good to have you on. thanks so much. >> thank you, jim. >> boris. >> ahead, voters delivering a scathing message to president biden in a new cnn poll out today. the numbers showing democrats have a serious dilemma. and it's giving one specific republican a big opening in next year's election. plus, he's flying people into space, reinventing the auto industry, taking over social media companies. and now reportedly playing a unique role in russia's invasion of ukraine. why tech billionaires elon musk is asking how am i in this war? 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