A Prince George’s County teenager who was a prosecution witness in an upcoming murder case was fatally shot inside his Fort Washington home, and detectives are investigating whether the young man was targeted because of the testimony he was expected to provide.

County State’s Attorney Angela Alsobrooks said that officials had learned in March of a credible threat against 19-year-old Kquantae M. Fisher but that he and his family declined witness protection services. Fisher was found dead in his home in the 6100 block of Kildare Court about 9:25 a.m. Wednesday. Officials said Fisher appeared to have been “targeted,” although they stopped short of saying they think he was killed because he was a witness.

“That’s just one possible motive, but we’re looking at all possible motives in this case,” Prince George’s Police Chief Mark Magaw said.

Magaw said there was no sign of forced entry into Fisher’s home. Officers found his body after his family called police and asked that they check on him.

Fisher was one of two teens initially charged in the January slaying of Marcus Antonio Jones, 16, a Friendly High sophomore. Alsobrooks said prosecutors dropped the charges against Fisher after determining that he was not involved in the killing, although he was expected to testify against the alleged gunman, Akil Ings, now 18.

After Jones was killed, police said they thought that the shooting was gang-related. They said that Ings and Fisher were members of a gang known as Baby Haiti and that Jones was a member of a rival group known as the Danger Boys. The gangs feuded at a house party in Fort Washington, police said at the time, and Jones was gunned down after he left the party.

On Tuesday, Fisher appeared in court to be served papers to testify at Ings’s trial scheduled for February, Alsobrooks said. Online court records show Fisher also was charged in July in a drug case.

Alsobrooks said she could not provide details on how Fisher had been threatened. If he and his family had accepted protection, they would have been moved to another county.

IfFisher was slain because he was a witness, it would be the second recent case in Prince George’s. In December, 25-year-old Nicoh Mayhew, who was cooperating with law enforcement officials in a double-murder case and who had also declined witness protection, was fatally shot outside a Seat Pleasant apartment in an incident prosecutors say was a hit orchestrated from the Prince George’s jail. They have charged Mayhew’s nephew in the slaying.

Alsobrooks said she didn’t want Fisher’s death to keep witnesses in other cases from stepping forward.

“In this case, it is very important to note that, unfortunately, Mr. Fisher was associated with a gang, so we believe that these circumstances are isolated and distinguish it from other witnesses who are not gang-associated,” Alsobrooks said. “We unfortunately are not able to force individuals to accept the protection we offer, but we do urge it.”

Jones’s slaying caused tension at Friendly High, even sparking a brawl that police attributed to emotions running high. It also prompted an internal sheriff’s office investigation because there was a warrant for Ings’s arrest that went unserved in the week before the killing.

The lawyer listed for Ings in online court records could not immediately be reached for comment.

After Jones was killed, detectives seemed to want to talk to Fisher about other people involved in the crime, said Fisher’s mother and stepfather, who declined to give their names.

“They were saying that they feel his life is in danger and they need to take him down for questioning,” his stepfather said at the time. “They knew for a fact that he was out at this scene or whatever, but they were saying that he was a potential witness.”

Reached Thursday, Fisher’s mother declined to comment.

Barbara Beverly, Jones’s grandmother, said in an interview Thursday that she had heard some time ago — she could not be sure when — that police had released the older of the two teenagers arrested and charged in her grandson’s slaying. She said she did not hear that from authorities, though, and could only make assumptions about why it had happened.

“I don’t know how it works,” she said. “I guess since he wasn’t the actual shooter, they let him ago.”

In light of Fisher’s death, Alsobrooks said her office will have to reassess its case against Ings. But despite the loss of an important witness, she said she is confident that her team will come through with a conviction: “It is our intent to first of all bring the individual who killed Mr. Fisher to justice, and we will certainly bring Mr. Akil Ings to justice as well.”