Investigation underway after veteran Cleveland police officer shot and killed

Cleveland police officers stand at the site of the shooting.

(CNN)A police officer was killed in the line of duty in Cleveland, Ohio, on Thursday night. The FBI has identified him as Detective James Skernivitz and said reward money is available for information leading to an arrest and conviction.

Three persons of interest have been identified and taken into custody, arrested on unrelated charges, according to Cleveland Director of Public Safety Karrie Howard. They include two juveniles and one adult.
"We think there is a connection to those three and maybe others, so we're asking for the public's help," Cleveland Chief of Police Calvin Williams said.
However, Williams would not provide any details about Detective Skernivitz's assignment Thursday evening. "He was doing his duty to protect the citizens of the city and I'll leave it at that," he said.
    He also didn't hint at any possible motive for the shooting. "And again, we don't know the motive to this, it could have been random, it could have been targeted. We don't know," Williams added.
    Detective Skernivitz had been assigned to the Cleveland Division of Police gang impact unit and was most recently sworn in as a Violent Crimes Task Force officer with the FBI, according to Howard.
    Jeff Follmer, Cleveland Police Patrolmen's Association President, told CNN affiliate WOIO, "It's bad, this a bad one. And they're all bad -- this one hurts."
    The shooting occurred in the city's West Side, in the area of W. 65th Street and Storer Avenue, the police department said in a tweet. The street was shut down, WOIO reported.
    "I want to give my condolences to the family and on behalf of the City of Cleveland," Mayor Frank Jackson said earlier.
    Detective Skernivitz had been a 25+ year veteran, according to police. "Cleveland lost one of its finest tonight in the line of duty," Chief Williams said during a press conference early Friday morning.
      Meanwhile, a second officer, identified as Nicholas Sabo and belonging to the same division, died by suicide, according to Howard. But Williams said so far there are no details on the relationship between the two officers. He added that most of the officers in the division know each other, but he didn't have any information yet on whether or not the two worked together.
      "I don't think anybody out there can really understand what the division is going through. The loss of an officer in the line of duty, especially to violence, is a terrible tragedy. But two officers in one night, is really bad," Williams added.