BOSTON (CBS) – Boston Police said at a Friday press conference that the death of seven-year-old Kyzr Willis was an “unfortunate accident” and foul play is not suspected.

Willis was reported missing on Tuesday while he was attending a summer program in the area of M Street Bath House.

His body was found four hours later in the water about 20 yards off of Carson Beach.

Boston Police Commissioner William Evans said Friday preliminary investigation shows there was no foul play involved in his death. He died from an accidental drowning.

Counselors told police that Willis was not a strong swimmer and was learning in the water earlier in the day.

Police Update on Investigation Into Death of Kyzr Willis

There were 56 children participating in the program under the supervision of about 25 counselors. There were also eight lifeguards, a director, supervisor and assistant supervisor at the beach when Willis went missing.

A day later, Boston Mayor Marty Walsh announced that the director of the camp had been placed on paid administrative leave.

State Police search for Kyzr Willis off Carson Beach (WBZ-TV)

State Police search for Kyzr Willis off Carson Beach (WBZ-TV)

Evans said everyone involved in the camp is having a difficult time dealing with Willis’ death.

“He was a good child. They watched out for him and they’re upset that Kyzr suffered the tragedy he did,” said Evans.

Evans said during Friday’s press conference that he has briefed the Willis’ family of the preliminary results of the department’s investigation.

Willis had exited the water along with the rest of the campers when instructed to by counselors. It is not clear when he got back in the water, Evans said.

“You lose track of a child for even a few seconds, a tragedy can happen,” said Evans.

Following the Boston Police press conference, Walsh called Willis’ death a “terrible tragedy” as he released the city’s plans to strengthen safety at drop-in camps.