BATON ROUGE, La. (AP) — A suspected serial killer was indicted Monday on murder charges in a string of shootings that killed three men and wounded a fourth.

A grand jury indicted Ryan Sharpe, 36, on charges including first-degree murder in the three shootings that occurred in East Feliciana Parish, according to District Attorney Samuel D'Aquilla.

The fourth shooting occurred in neighboring East Baton Rouge Parish, where Sharpe has been jailed since his arrest last month.

The shootings occurred in a rural area north of Baton Rouge and left residents on edge for weeks after he first killing in July. The victims were middle-aged or older white men who were shot at their homes or on their property. Sharpe, the owner of a plumbing company, also is white.

An attorney for Sharpe couldn't immediately be reached for comment.

A law enforcement official told The Associated Press last month that Sharpe wasn't a suspect in the shootings until he called East Feliciana Parish Sheriff Jeff Travis' office on Oct. 11 and identified himself as the killer. The official spoke only on condition of anonymity because the investigation was ongoing.

Sharpe is charged with first-degree murder in the Oct. 9 shooting of Boy Scouts employee Brad DeFranceschi, who was gunned down while trimming weeds in front of his house. DeFranceschi lived on Boy Scouts camp property in Clinton, a town of 1,600 people about 30 miles (50 kilometers) from the state capital.

Sharpe is charged with second-degree murder in the July 8 shooting of 62-year-old Tommy Bass, who was killed in the carport of his home. Sharp also is charged with attempted first-degree murder in the Sept. 12 shooting of 47-year-old Buck Hornsby, who was wounded while exercising on his property.

Carroll Breeden, 66, was shot to death Sept. 19 while doing yard work in front of his home in East Baton Rouge Parish. A judge appointed the Baton Rouge-based public defender's office to represent Sharpe in that case, which hasn't gone to a grand jury yet.

D'Aquilla said Sharpe is scheduled to be arraigned in East Feliciana Parish on Nov. 28.

Travis, the sheriff, has said Sharpe confessed when investigators questioned him after his arrest. Travis also has said detectives found "significant physical evidence" linking Sharpe to the shootings.