Sen. Pleasant Bridgewater has been held since Thursday in the case, said Senior Assistant Commissioner of Police Marvin Dames.
A second suspect, ambulance driver Tarino Lightbourne, was detained on Friday, Dames said. Lightbourne was quoted by several tabloids describing efforts to revive Travolta's 16-year-old son Jett.
Jett died of a seizure earlier this month at a family vacation home on Grand Bahama island.