A district attorney reviewing the case of a Massachusetts State Police recruit who died after a boxing training exercise said Monday that another agency must investigate because the man had worked in his office as a victim witness advocate.

Enrique Delgado-Garcia, 25, of Worcester, died at a hospital last week, a day after the exercise at the Massachusetts State Police Academy in New Braintree, in Worcester County, about 80 miles (130 kilometers) west of Boston.

Before training began in April to achieve his life-long dream of joining the state police, Delgado-Garcia had worked for 18 months at the county attorney's office, where he often stayed late to help people, District Attorney Joseph Early Jr. said at a news conference.

“Because of this close relationship, someone else will be handling this matter,” said Early, with tearful members of Delgado-Garcia's family and former co-workers nearby. “There's no way this office can handle this. Everyone loved Enrique.”

Early said detectives assigned to his office will continue to investigate, but they will work with whichever agency takes over. He said he spoke with several entities in the state about taking over the case, but declined to name them. He said it would not be another district attorney's office.

“I want it done by someone who doesn't have a stake in its outcome," he said.

A state police spokesperson said the academy’s on-site medical team responded immediately after Delgado-Garcia became unresponsive during the training exercise on Thursday, and that the recruit wore boxing gloves, headgear and a protective athletic cup.

The medical team determined that he required urgent medical care and took him to the hospital, where he died Friday.

Delgado-Garcia’s mother told reporters with NBC10 Boston and Telemundo Nueva Inglaterra that he was hit and injured.

“I don’t understand why it was so rough if it was just training,” Sandra Garcia said in Spanish. “I want them to explain it to me, that the state explains to me what happened with my son. … Why did he hit him so hard that it killed him, that it destroyed his brain and broke all of my son’s teeth and he had a neck fracture too, my son.”

She continued: “The doctor says that the injury my son received was more like something he would have gotten if he had been in crash with a car that was traveling 100 miles per hour, that the blow so powerful that that boy delivered to my son.”

Garcia and other family at the news conference declined to speak.

Early said an autopsy report has not been finalized.

“We don't have a cause and manner of death to release at this time," he said.

Regarding the training exercise, he said: “We know it was in the boxing ring. It was videotaped.” Early said he hadn't seen the video.

Delgado-Garcia's class is scheduled to graduate Oct. 9. He was administered the oath of office by state police in the final hours of his life, the state police spokesperson said.

Massachusetts Gov. Maura Healey issued a statement saying she was heartbroken about the loss of Delgado-Garcia.

Early described him as “a fine, upstanding young man” with a smile that “lit up a room.”

“These guys are hurting,” he said, referring to the workers in the room.