LOS ANGELES (Reuters) - Shawne Merriman, a star linebacker for the NFL's San Diego Chargers, will not be prosecuted over allegations he assaulted his reality TV star girlfriend, a San Diego County official said.

"Our office has determined there is insufficient evidence to prove beyond a reasonable doubt that any crime was committed," Bonnie Dumanis, San Diego's district attorney, said in a statement issued late on Friday.

Dumanis said her office closed the case, which arose after Tila Nguyen, a singer and television personality known as Tila Tequila, called police on September 6 and accused Merriman of choking her and trapping her in his mansion.

She signed a citizen's arrest charging him with battery and false imprisonment, police said.

(Reporting by Lisa Baertlein, editing by Jackie Frank)