Groton — Poquonnock Bridge firefighter Tim Devine "immediately went into crisis mode" when he learned on July 23 that he was the subject of an investigation into alleged sexual misconduct involving teenage boys, police said.

A police source said Thursday that Groton City and Groton Town police departments are investigating the allegations. The source said there are between three and 10 victims, but there could be more who have not yet come forward. Police said Devine is the only person being investigated.

Another source with intimate knowledge of the case said the victims are teenage boys who worked out at the CrossFit gym Devine owned in Groton.

"The City of Groton Police Department is participating in an investigation along with several area police departments concerning Timothy Devine, the owner of Cross-Fit Groton. The investigation is ongoing and additional information is not being released at this time," Groton City Police Capt. Thomas Davoren said Thursday in a press release.

Police never got to question Devine, 30, of 33 Crown Knoll Court, Groton, because he took his own life during the early hours of July 24, ending an hours-long armed standoff with police at the University of Connecticut's Avery Point campus.

During the standoff, UConn sent out an alert of an armed man on campus and advised people to evacuate. The incident occurred just three days after 12 people were killed and 58 were injured during a shooting in a Colorado movie theater.

State's Attorney Michael L. Regan, who would receive the police report when it is complete, also confirmed Thursday that there is an investigation in progress, but declined to identify its nature.

Lt. John W. Varone, detective commander in the Groton Town police department, would not comment on the specific case. But he said that police have an obligation to fully investigate any allegations that are brought to them, even if the subject of the investigation is deceased and the investigation can't result in an arrest.

Devine opened CrossFit Groton about a year ago and was the sole owner of the gym whose programming is described as "the principal strength and conditioning program for many police academies and tactical operations teams, military special operations units, champion martial artists, and hundreds of other elite and professional athletes worldwide," according to the main CrossFit website.

Officials at CrossFit headquarters could not be reached for comment Thursday.

At about 5 p.m. on July 23, local police were notified of a despondent person who could be suicidal and armed. Police located Devine's car on campus at about 10 p.m. and soon after found him standing on some rocks near the shore. He refused police requests to surrender his weapon.

The university sent out an alert at 11:35 p.m. that there was an armed man on campus. The alert instructed anyone on campus to leave.

A group of high school students in a summer program was at Avery Point at the time, according to a university spokeswoman. The students were kept indoors, guarded by UConn police. No college students were on the campus, which does not have dormitories.

Local and state police talked to Devine via cellphone until he threw his phone away. They then tried to disarm him through non-lethal means including bean bags, loud noises and bright lights, state police said.

Devine shot himself at about 4 a.m., police said, and was pronounced dead at the scene.

State Police Lt. J. Paul Vance said Thursday that state police are not involved in the investigation. Vance said state police were involved in the suicide investigation because it happened on state property.

CrossFit Groton remains closed.

Day Staff Writer Julianne Hanckel contributed to this report.

i.larraneta@theday.com