Prosecutors have dropped the charges against a Mount Rainier man accused of beating a 72-year-old man with a baseball bat last month.

They said they even though the victim picked the man’s photo out of a lineup, other evidence led them to charge a different man.

Investigators no longer believe that Justin C. Strong, 22, was responsible for the Sept. 15 attack in Colmar Manor that left a 72-year-old severely injured — even though the 72-year-old initially identified Strong as his attacker, prosecutors said. Prince George’s State’s Attorney’s spokesman John Erzen said that investigators instead believe Edwin M. Gonzalez, 20, of Colmar Manor was responsible for the brutal beating. He was arrested and charged with attempted first-degree murder and related counts on Sept. 29, the same day Strong was released from jail, according to Erzen and court records.

Investigators still believe the circumstances of the attack were these: Just before 6 a.m. on Sept. 15, someone pulled out a knife and demanded the wallet of a 72-year-old man waiting at a bus stop in the 3800 block of Bladensburg Road. After the 72-year-old refused, the would-be robber left and returned with an aluminum baseball bat, inflicting a severe beating until someone passed by and yelled for him to stop.

The 72-year-old was seriously injured but survived, authorities said.

Erzen said that after the attack, investigators showed the 72-year-old a photo lineup containing photos of both Strong and Gonzalez. The 72-year-old, he said, identified Strong as his attacker. Police took him into custody on Sept. 21 and charged him with attempted first-degree murder and related counts, authorities have said.

Some time later though, a man talking to police in connection with an unrelated crime told investigators they had charged the wrong man, Erzen said. That man pointed investigators to three other people with knowledge of the case, and one of those people linked Gonzalez to the attack, he said.

Erzen said investigators talked to Gonzalez, and that conversation and other evidence helped them “feel comfortable with releasing Strong and charging Gonzalez.” He declined to say what specific evidence prosecutors had against Gonzalez because the case is ongoing, but he said surveillance footage showed a man who “didn’t seem to fit the stature” of Strong.

Efforts to locate phone numbers for Strong and Gonzalez were unsuccessful, and court records did not list a lawyer for either man.