Mexican authorities have arrested a state police officer in connection with last week's casino arson fire in Monterrey that killed 52 people.
The Associated Press reports a surveillance video shows the officer in a vehicle outside the upscale Casino Royale. Few other details were immediately released.
Authorities arrested five other suspects, believed to be members of the Zetas drug cartel, on Monday.
Investigators have not given a motive for the killings, but they are exploring whether drugs or an extortion plot are behind the attack.