Officials in Rochester, New York, said on Thursday that the dead body found in a reservoir that supplies drinking water to residents earlier this week was a missing person who had been in the water for just under a month. The discovery of the man's body had prompted a temporary boil water advisory. 

Rochester Mayor Malik Evans said at a press conference that officials discovered the body in the Highland Park Reservoir Tuesday at around 8 a.m. As soon as the body was discovered, Evans said that the reservoir was "shut off and bypassed as part of the city's water distribution system." 

"Our testing has shown no issues," Evans said. "...Out of an abundance of caution we have issued a boil water advisory. ... The reservoir will not be back in service until it has been drained and cleaned."

Police said Thursday that the body was identified as 29-year-old Abdullahi Muya, a Rochester resident who had been missing since February and was last seen on Feb. 18. Their investigation found that his body had been in the water for nearly a month after he entered the gated area on Feb. 24.

"After entering the gated area, at approximately 6:30 a.m., Mr. Muya appears to have slid down the side of the reservoir, into the water, where he tragically died," police said. "There was no one else present at the time of Mr. Muya's death and their [sic] does not appear to be any criminal element to this investigation." 

Despite the body's prolonged exposure to the reservoir, Evans said on Thursday that water quality tests ordered by the county "confirmed the safety of the water supply." The boil water advisory has also been lifted. 

"Our own data collected in the weeks and months prior to that mirrored those findings," Evans said, saying he drank some of the city's water this morning. "As I have always touted, the quality of our water wins awards regularly. So our water was never in question." 

The discovery of the body a month after Muya's death "obviously calls into question how could he have not been detected in the reservoir being there that long," Evans said, adding that it's a question "all of us are asking, me in particular." According to the city, the reservoir is inspected daily.

"The bureau is patrolled regularly by city security and water bureau personnel," Evans said, adding that the site is filled with sensitive, high-tech equipment that regularly checks water quality, heat and other items that should, in theory, have been able to detect a disturbance. "And yet, we did not know that Mr. Muya had gotten into the area or that he had entered the water." 

Water in the reservoir is 15 feet deep and Muya's body was found "well below the surface," Evans said, within the shadows of the north side of the reservoir. This could explain why he was not before seen, he said. 

"Reflection waves and shadows at this specific location can obscure the view of the bottom," he said. "Obviously, this is very traumatic for the water bureau team." 

The city is now working on ways to ensure there are no more physical breaches in the future. The process for refilling the reservoir will take place over the next few months, the city said. 

In:
• Water Safety
• Rochester
• Boil Water Advisory
• New York

Li Cohen is a social media producer and trending content writer for CBS News.