The state added a charge of attempted murder to its case against accused arsonist Marwan O. Chankar on Thursday as jury selection was set to begin in New London Superior Court.

Prosecutor David J. Smith said that as his office prepared the case for trial, they developed evidence that indicated Chankar was attempting to kill Henry Wickham, an occupant of a five-unit apartment building at 143-145 Rockwell St. in Norwich, when Chankar allegedly torched the building on July 9, 2011. The new information came from witnesses in the case, Smith said.

Chankar, 37, who is already serving a 58-month prison sentence for being the getaway driver in two bank robberies, had previously rejected the state’s offer to resolve the case in exchange for a 10-year prison sentence.

Smith added the attempted murder charge to the existing charges of first-degree arson and first-degree criminal mischief and removed a charge of first-degree burglary. He said there is evidence Chankar was trying to kill not just one, but three occupants. Chankar could be sentenced to up to 50 years in prison if convicted on all charges at trial. His so-called “exposure” is the same despite the new charge, because attempted murder and first-degree burglary both carry a maximum prison sentence of 20 years, according to Smith.

Defense attorney Theodore Koch objected to the new charge, which he argued falls under the category of “prosecutorial vindictiveness.” He said that, leading up to the trial, there was no indication attempted murder would be charged and that the new charge is solely a result of his client exercising his protected legal right to a trial.

Jongbloed ruled that the state had the right to amend the charge while preparing the case for trial.

“Under the circumstances, I don’t think the defense has shown it was in any way vindictive,” the judge said.

Jury selection will begin today, and testimony is scheduled to begin Oct. 27.

Chankar was homeless and had been staying with a tenant in the apartment but was asked to leave after he and the tenant got into an argument about an hour before the fire occurred, according to the arrest warrant affidavit. He also had been squatting in a vacant apartment on the second floor.

Norwich police allege Chankar used charcoal lighter fluid to start the fire in the vacant unit. They said the fire caused more than $400,000 in damage and displaced about 10 residents. Five of the city’s fire departments responded to the large blaze, and two firefighters suffered minor injuries.

During the investigation, Deputy Fire Marshal Jacob Manke observed irregular burn patterns on the kitchen floor, and his K-9, Baxter, alerted him to the presence of an accelerant, the affidavit says. Tests of floor materials and debris by the state forensic laboratory confirmed the presence of a compound with the same properties as lighter fluid.

A witness came forward who said Chankar told her that after he argued with the tenant about crack cocaine and was asked to leave, he went to the vacant apartment and lit the fire by igniting some curtains.

Koch is attempting to suppress statements that Chankar made to police two weeks after the fire, when they approached him as he waited to meet his mother outside a clinic on West Thames Street. Koch said the officers did not inform Chankar he was free to leave, had a right to remain silent and had a right to an attorney.

The judge heard arguments on the suppression motion Thursday but held off on a ruling to allow Koch time to present additional evidence.

k.florin@theday.com

Twitter: @KFLORIN