A seventh suspect was arrested Tuesday in the gang rape of a 15-year-old girl outside a high school homecoming dance while as many as 20 people watched without calling police.

Police arrested an unidentified 21-year-old man from Richmond on suspicion of rape, rape in concert with force and other charges that could lead to life in prison if he is convicted, police Lt. Mark Gagan said.

The man was being held on $1.2. million bail.

"We are actively pursuing more suspects," Gagan said. "There is still a lot more work that has to be done."

A healing rally and candlelight vigil for the victim was planned later Tuesday at Richmond High School, the scene of the rape in the low-income Northern California city.

Prosecutors have filed charges against five other suspects in the Oct. 24 attack, including 18-year-old Jose Carlos Montano of San Pablo late Monday.

Cody Ray Smith, 15, pleaded not guilty to charges, while Ari Abdallah Morales, 16, and Marcelles