JERUSALEM — An Israeli border police officer has been arrested on suspicion of involvement in the fatal shooting of two Palestinian teenagers in the West Bank during a protest in May, officials said on Wednesday.

Citing orders not to discuss the case, the police provided few details, but Israeli news media reported that the officer was suspected of shooting at least one of the teenagers and that his commander was under house arrest, apparently under suspicion of having helped cover up the episode.

Further charging the atmosphere at a time of heightened Israeli-Palestinian tensions and religious friction, a mosque in a village in the West Bank was damaged overnight in what was said to be an arson attack, and a firebomb was thrown at an old synagogue in an Arab town in northern Israel, the police said. There were no reports of injuries in either attack.

In the May shooting case, video taken from a security camera at a business in Beitunia, a town outside Ramallah, showed that the two youths were knocked down, apparently by gunfire, about an hour apart.