Vanessa Marcotte, the 27-year-old Boston University graduate killed while jogging in Princeton on Sunday, struggled with her attacker and probably left him with scratches, scrapes, and bruises, the authorities said Thursday.
Worcester District Attorney Joseph D. Early Jr. said during an afternoon briefing that anyone who saw a man with those types of injuries when they were fresh earlier this week should call the State Police tip line at 508-453-7589.
Early also said investigators now believe Marcotte was killed between 1 p.m., when she left her mother’s house on Brooks Station Road, and 3 p.m.
He said anyone who saw a car driving or parked on the road during that time period should call the tip line.
Previously, investigators had focused on a slightly wider time frame, 1 p.m. to 4 p.m.
Marcotte was a Leominster native and a 2011 graduate of BU who had been working for Google in New York City.
— Sera Congi (@seracongi) August 11, 2016
A law enforcement official said her body was burned, and authorities are investigating whether she was sexually assaulted.
Early spoke for just a couple of minutes on Thursday and did not say how investigators determined Marcotte’s attacker was a man, or how they narrowed the time frame of the case.
He did not take questions from reporters.
About two dozen state troopers returned Thursday to the wooded area where Marcotte was killed.
The troopers were from the Special Emergency Response Team, a specially trained search team, and the Crime Scene Services unit.
The search was conducted as part of the ongoing investigation, said State Police spokesman David Procopio.
The number of tips in the mysterious case has mounted to more than 300, and a steady flow continues to come in, Procopio said.
Marcotte had been visiting her mother in Princeton. The authorities are urging town residents to be careful and observant.
Vigils have been held for Marcotte, who was described earlier in the week by her grief-stricken father as “a great kid” who was dedicated to her job.
“I could only ask for your prayers, that they find [who] did this,” John Marcotte said in an interview in front of his home on Tuesday afternoon.
“That’s all we want. That’s all we want: justice.”