Worcester County District Attorney Joseph Early Jr. speaks to media outside the police department in Princeton, Mass., on Saturday, April 15, 2017 about the arrest of a man in connection to death of Vanessa Marcotte. Authorities said DNA evidence and an attentive state trooper helped find Angelo Colon-Ortiz, who authorities believe killed the New York City woman in 2016, who was out jogging near her mother's Massachusetts home. (Photo: Christine Peterson/Worcester Telegram & Gazette via AP)

The jogger’s body was found in the woods about a half-mile away from her mother’s house in Princeton, Massachusetts. The 27-year-old, Vanessa Marcotte, had put up a fight against her killer, ripping some DNA from his body in her final struggle to survive.

The attacker’s DNA did not match anyone in CODIS. But a mix of high-tech analysis of genetic markers and a keen observation of a Massachusetts State Police detective who jotted down a suspicious license plate on his hand led right to the killer’s door, authorities announced Saturday.

Angelo Colon-Ortiz, 31, was arrested Friday by state police detectives and Worcester police officers. He is charged with aggravated assault and battery, and assault with attempt to rape, and is being held on $10 million bail, said Worcester County District Attorney Joseph D. Early Jr. Colon-Ortiz is scheduled to be arraigned tomorrow in Leominster District Court.

The exact circumstances linking the alleged killer to his victim have not yet been outlined by authorities. 

This undated driver license photo released by the Worcester County District Attorney's Office shows Vanessa Marcotte, of New York, whose body was found Sunday night, Aug. 7, 2016, in the woods about a half-mile from her mother's home in the town of Princeton, Mass., about 40 miles west of Boston. DNA evidence and an attentive state trooper helped find the man authorities believe killed Marcotte last summer who was out jogging near her mother's Massachusetts home, authorities said Saturday, April 15, 2017. (Photo: Worcester County District Attorney's Office via AP, File)

Marcotte was visiting her family in Princeton last August. The Google employee went for a walk on the afternoon of Aug. 7, 2016 and was shortly thereafter reported missing. Her naked and beaten body was found eight hours later by a big search party in the area.

DNA was eventually produced from under Marcotte’s fingernails, which was believed to have been the killer’s. But it matched no suspect in the database.

Hundreds of tips from the public poured in locally. The number of calls eventually topped 1,300.

After months of continued detective work, the authorities contacted Parabon NanoLabs, a DNA phenotyping company. Based on the genetic markers under Marcotte’s fingernails, the company determined a general description of the killer: a Hispanic or Latino man, about 30 years old, light- or medium-toned skin, average height and an athletic build.

The tips from the area also indicated the killer was driving a dark-colored SUV that would have been seen in the early afternoon near Brooks Station Road, where Marcotte’s body was found.

The combined description of a Hispanic man driving a dark-colored SUV was in the mind of the MSP detective who noticed a car passing by in nearby Worcester, said Early. The detective reached for a piece of paper, but could not find one. Instead, he jotted down the license plate number down on his hand.

The detective went to Colon-Ortiz’s apartment and left his business card with a note to call him. The suspect never called. So the detective returned to the apartment the next day and retrieved a voluntary buccal swab. The DNA matched, they announced.

“We’re very confident we have Vanessa Marcotte’s killer,” said Early, at a Saturday press conference. The district attorney further elaborated that the possibility of error between the match of the two DNA samples was 1 in more than 100 quintillion.

The murder charge has not yet been brought against the suspect, because the investigation is continuing, they added.

“I anticipate there will be a murder charge,” said Early, not further elaborating on the additional evidence to be made public. “There’s some evidence we have that puts him (Colon-Ortiz) in the area.”

Marcotte’s death in a relatively safe area of Massachusetts also became big news because it was just a few days after another high-profile death of a young female jogger. The Aug. 2, 2016 murder of Karina Vetrano, in Queens, N.Y., had similarly yielded a DNA profile that did not show up in CODIS or in other genetic databases. Authorities and Vetrano’s parents called for the use of familial searching (FS), a way to search genetic databases for people related to a person of interest in crimes. But the FS technique proved to be not needed—instead it was traditional detective work that led to the arrest of 20-year-old Chanel Lewis in February.