(Reuters) - A cigarette smoker high on opiates caused a New Jersey motel fire that killed four people in March, authorities said on Wednesday.

John Alberti, 45, can be seen on security video at the Mariner's Cove Motel in Point Pleasant Beach smoking in a public lounge where the fire started, the Ocean County, New Jersey, prosecutor's office said in a statement.

The blaze consumed the building, killing Alberti and three other people.

The county medical examiner found that Alberti, a longtime resident at the motel, was under the influence of opiates at the time, the statement said. A spokesman said the drug was most likely heroin.

The video, which had been damaged but was restored by law enforcement experts, showed Alberti falling asleep on his feet while leaning against a wall and smoking. It then shows him waking up and putting the lit cigarette on a chair, where smoke could be seen rising about 90 minutes later.

"This event tragically highlights how the impaired actions of those suffering from narcotic addiction can bring devastation to themselves and innocent unsuspecting individuals around them," said Ocean County Prosecutor Joseph Coronato in the statement.

"By no means is heroin addiction a victimless crime," he said.

Autopsies showed the four victims died of smoke inhalation, the statement said. The prosecutor's office said it found no criminal conduct and had closed its investigation.

(Reporting by Curtis Skinner; Editing by Ellen Wulfhorst and Doina Chiacu)