Strangled New York City Jogger Bit Her Attacker So Hard, Her Teeth Cracked: Source

The 30-year-old jogger found sexually assaulted and strangled to death this week in New York City "put up a ferocious fight" before her death, police said.
Karina Vetrano tried fighting off her attacker until the last moments of her life, police said at a Thursday news conference. Her body was found facedown in a Queens park Tuesday, about a dozen feet from the jogging trail, by her father.
A police source tells PEOPLE that Vetrano bit her attacker so hard, her teeth cracked. The source says
investigators have recovered DNA from Vetrano's bruised body.
"This woman put up a ferocious fight right to the end,"
New York City's Chief of Detectives Robert Boyce said during the news conference.
Boyce told reporters police believe the attack on Vetrano was random, and not committed by someone she knew.
Police are still searching the thick grass for additional clues, and detectives continue to comb through the marshlands at Gateway National Park in Howard Beach, looking for any evidence that can help them identify Vetrano's killer.
"We plan to chop down just about every weed in that location till we're satisfied that we've got all the evidence," Boyce said. "This is a remote area. A young
lady was running – still daylight – so I am hoping somebody saw something going into the park."
Vetrano was reported missing just after 5 p.m. on Tuesday, and her body was recovered shortly before 11p.m.
Boyce said Vetrano would typically run with her father,who decided to sit out Tuesday's jog because he was dealing with back pain.
When she didn't return, her dad called the police, who pinged her phone. It showed that she was in the brush
near the park's jogging path. The father went out with police and discovered her body 15 feet from the jogging trail, Boyce said.
Boyce said his detectives are also reviewing cell tower records to see if any other phones were present at the time Vetrano was killed.
Funeral services for Vetrano will be held at noon Saturday in Queens, preceded by a Friday wake.
Vetrano was a "popular, sweet girl," one person told the New York Times. "Everybody knew her," they said.
The bar where she worked called Vetrano a "dear friend," according to the Times.
"Karina was an amazing person; she will forever be in our hearts," the business wrote on Instagram, according to the paper.
A $10,000 reward is being offered for any information leading to an arrest of her killer.