Jurors sniffled and dried their eyes Monday afternoon as a forensic entomologist talked about the life cycles of maggots and flies during a slide show of photos of the decaying body of Crystal St. Pierre, who was found shot to death in Avondale five years ago.

Dr. Erin Watson, a university professor in Hammond who uses the scientific study of insects to help establish the time at which a person died, testified during the trial of Curtis Kyles that St. Pierre died during the daylight hours of June 10, 2010.

She was one of a handful of witnesses for the state Monday as prosecutors wrapped up their case against Kyles, the former death row inmate now charged in Jefferson Parish with kidnapping and second-degree murder.

The case, which is being heard by 24th Judicial District Judge Glenn Ansardi, could go to the jury as early as Tuesday.

Kyles, who would spend the rest of his life in jail if he is convicted, is accused of shooting St. Pierre in the back of the head in a field off an isolated gravel road in Avondale.

Kyles and his alleged accomplice, Chicwanda Forbes, tried unsuccessfully earlier that day to use St. Pierre’s Louisiana Purchase food stamp card to buy $200 in groceries, prosecutors said.

After the PIN Kyles tried to use failed several times, he and Forbes returned to the apartment complex where he and St. Pierre lived, banging on the door of the unit where St. Pierre was staying.

Witnesses said Kyles was yelling obscenities and demanding “my money” when St. Pierre stepped outside and Forbes grabbed her, began punching her and dragged her down the stairs.

Forbes forced St. Pierre into the back seat of a maroon Mitsubishi Galant and got in with her. Kyles got in the driver’s seat and sped off, a witness said.

Cellular phone records indicated the car headed toward Avondale, where, according to Forbes, Kyles forced St. Pierre out of the car and to her knees and shot her once in the back of the head.

The pair then fled to rural Mississippi, where the family of Kyles’ former girlfriend lived. They were living in an abandoned trailer there when they were arrested several days later.

Forbes, who is serving 15 years on the kidnapping charge but had the second-degree murder charge against her dropped in exchange for her testimony, said Kyles had her wrap the gun he used in a shirt and throw it out the window.

Investigators who went back with Forbes to look for the murder weapon could not find it. However, police searching Kyles’ apartment found a box of .38-caliber bullets, the same caliber as the bullet found in St. Pierre’s skull.

Jurors last week heard testimony from witnesses who were with Kyles and Forbes while they were in Mississippi. Kyles’ son, however, gave testimony that appeared to conflict with statements he gave to police after Kyles and Forbes were arrested.

Curtis “Chester” Burnes, who drove his father and Forbes to a north shore bank in the days after St. Pierre’s death, testified that his earlier statement to police that his “dad (screwed) up” after talking on the phone with his mother was in fact only his assessment of the couple’s chances of getting back together again.

Kyles’ previous murder conviction — not admissible in the current case — was overturned by the U.S. Supreme Court. He was convicted in 1984 of shooting an elderly woman in the parking lot of a New Orleans supermarket and put on death row. In 1995, however, the U.S. Supreme Court overturned his conviction after finding the prosecution had withheld evidence that would have helped his case.

Follow Chad Calder on Twitter, @Chad_Calder.