Arrests have been made in the September killing of a Central High School junior and the February slaying of an elderly Capitol Heights woman, police announced Monday.

Travon Bennett, 20, of Bryans Road, Md., is charged with murdering 18-year-old Marckel Ross. James Alphonso Ward, 46, of Capitol Heights, is charged with murdering 71-year-old Geraldine McIntyre, according to court documents.

"We will do everything in our power to protect those who are vulnerable in our community, the elderly, the young," Prince George's County State's Attorney Angela Alsobrooks said.

The killings, while unrelated, both occurred in Capitol Heights, were both described as robbery-related and the suspects in the two cases both face charges in other incidents.

On Sept. 11, Ross was walking to school when Bennett attempted to rob him, shot him and fled the scene, authorities said.

Bennett was arrested at the scene of an armed robbery on Oct. 31 that occurred near where Ross was killed. A .38-caliber revolver was recovered from that robbery, and authorities determined the weapon was used to kill Ross. Also, according to a court document, a co-defendant in the October robbery told detectives that Bennett had told him that he had killed Ross.

Bennett has been in custody since the October robbery, in which the victim's cigarettes were taken. He has been linked to a few similar incidents, including one on May 31 when he allegedly shot someone during an attempted robbery, said police Maj. Mike Straughan.

Ross was the second of six Prince George's County students to be slain so far this school year. Arrests have now been made in four of the students' deaths, and police are investigating leads in the other two slayings and are hoping to close the cases soon.

McIntyre was found stabbed to death in her home on Feb. 9. A flat-screen television was taken during the incident.

Ward, who reportedly had been helping McIntyre around her house, was identified as a suspect in her death a few days after the stabbing. He has been incarcerated since the middle of the month, when he was arrested on a warrant for an unrelated burglary, Straughan said.

Authorities got a break in the case Friday when they recovered the TV. A witness told police that on the day of the slaying, Ward brought the TV to the witness' home and sold it to the witness for $40, according to a charging document.