crews find nothing, police shea bruce hansen was swimming near route 27 on friday when he went under. >> another reason for me not to go, the more i hear about it. >> reporter: at the lock raven reservoir, these people are afraid to swim, but police say plenty of others are not, even though it's illegal. baltimore search members have found three people, they have all died. it's the conditions of the water in a reservoir that makes it so dangerous. it can be export huenemely cold and in some cases, 100 feet deep. still, they take the risk, including this group of teens that don't want to be identified. >> when you get to the high one, it gets a little scary. >> reporter: it's not just reservoirs that can be deadly. police warn against swimming in any of the waters especially if you are drunk or high. again, crews will focus theirists on finding bruce hansen first thing in the morning. for now, they are calling the mission a recovery, not a rescue. >> all right, thank you. >> rangers still monitor the reservoirs for illegal swimming. in the past few weeks, they have written dozens of ci