CONCORD — A Merrimack County Superior Court jury is deciding the fate of a Concord man charged with lighting a fire that resulted in the death of an elderly man more than 15 years ago.

Testimony ended Monday in the month-long cold-case murder trial.

Both sides delivered closing arguments in the case, where Richard Ellison, 47, faces both first- and second-degree murder charges.

He is accused of starting a fire in a duplex that resulted in the death of Robert McMillan, 85, in 2005. Although alive when taken out of his burning duplex, McMillan later died at Massachusetts General Hospital.

“This was intentional and this was deadly,” homicide prosecutor Rachel Harrington told the jury last month.

The trial, which had been delayed because of COVID-19, started Aug. 13. The state called 42 witnesses and the defense called two.

Ellison was arrested in 2018. Prosecutors claim he set the fire out of rage and had assaulted McMillan before setting the fire.

The defense claimed that police mishandled evidence in the case, which led them to the wrong man. They argue the fire could have been accidental.

“Clues were lost and misunderstood,” defense lawyer Caroline Smith told jurors during opening arguments.