The murder trial of an Industry man accused of killing a young woman more than thirty years ago has entered its fourth day.Throughout the trial of 56-year-old Jay Mercier, prosecutors have been trying to put him at the scene where 20-year-old Rita St. Peter’s body was dumped back in July of 1980. After the testimony of one the primary investigator in the case, prosecutors may be getting closer to doing just that.Tuesday Paul Stewart, the primary detective investigating the case 32 years ago, told the jury that Mercier gave conflicting accounts of his actions the night St. Peter was murdered. Â Stewart testified that during his initial interview with Mercier in 1980 he told police he had not picked up any hitchhikers or women that night, and he also told police he had not been on the Campground Road in Anson, the road St. Peter’s body was discovered, the night of the murder.Â However, in a second interview Stewart conducted with Mercier in September of 1980, Mercier started backtracking on his previous statements. Stewart told the jury that Mercier admitted to being in Anson that night and when he was asked once again if he had been on the Campground Road that night he started to waver from his original story. Â “He said he could have been on the Campground Road,” Stewart told the jury.Stewart claims Mercier also told him during that second interview he had drank several six packs of beer and he might have picked up a hitchhiker. Â “He said he must have blacked out, because if he picked up a hitchhiker, especially a girl, he would have remembered that.”Stewart also testified that police searched extensively for the tire iron that Mercier had kept in his truck, but never located it. Â Police believe St. Peter was beaten to death with a blunt, heavy object, possibly a tire iron. Â Stewart said Mercier didn’t know where the tire iron was. Â According to Stewart, Mercier told police he had put the tire iron in the cab of his truck because he was having a problem with someone at the Depot and wanted it nearby for protection. The Depot is the MadisonÂ bar where Rita St. Peter was last seen before, according to witness testimony, she was seen highly intoxicated walking across the bridge from Madison into Anson.Â During cross examination of Stewart by defense attorney John Alsop a new theory the crime emerged. Â Alsop, using Stewart’s 32-year-old police report as a reference, brought up an abandoned vehicle found in Somerset County back in 1980. Inside that vehicle a red mallet was found. Â “Why was that of interest to you?” Alsop asked Stewart. Â “Because it could be used as a weapon,” Stewart responded. “Was there not blood and hair found on the mallet?” Alsop asked. “Yes,” Stewart said.That mallet was turned over to Mark Anton in the Maine State Police Crime Lab shortly after it was found. Stewart wrote in his report that the mallet was ruled out as a possible murder weapon.The prosecution will continue presenting their case this afternoon. The trial s expected to wrap this week.