A person of interest in an arson fire that killed three people and injured another at a Metairie apartment building Tuesday morning is behind bars.

Authorities said they believe Terrill Normand, 58, of Metairie, may have played a part in the two-alarm fire that began a little before 3 a.m. in the 2300 block of Harvard Avenue.

Normand was picked up in the neighborhood on an unrelated attachment a short time after the fire, said Sheriff Newell Normand, who is not related to Terrill Normand.

The sheriff said Terrill Normand has refused to speak to investigators and has invoked his right to an attorney.

Detectives, however, have learned that Terrill Normand once had a relationship and “infatuation” with one of the fire victims, the sheriff said. He said evidence also has placed Terrill Normand near the scene about the time the fire began.

State Fire Marshal Butch Browning said Tuesday that an accelerant was used to spread the fire, which he said began in a stairwell outside the unit where the victims were staying.

Mark Bone, the Jefferson Parish coroner’s chief investigator, said Wednesday that the office had tentative IDs on the two men and one woman who died, but that the names are being withheld pending notification of family.

Authorities have said that whoever caused the fire likely will face arson and homicide charges.

Newell Normand said Wednesday that a first-degree murder charge could be brought against any suspect arrested in the case because of the nature of the crime.