A cardiologist suspected in a hit-and-run that killed a nurse who had stopped to help a crash victim on a Fresno area highway was arrested after a months-long investigation aided by an anonymous tip, authorities said.

Dr. James Leonard Comazzi, 68, was arrested Monday at his Sonora home and booked into Fresno County Jail. He posted bond Tuesday.

California Highway Patrol Lt. Austin Matulonis made the arrest announcement in front of the family of Juliana Ramos, a 26-year-old nurse and the mother of three who lived in Reedley.

Crimestoppers Tip Leads to Doctor

Ramos was killed on Feb. 10 while trying to help the driver of a car who had major injuries after a collision with a big rig on Highway 99 near the Manning Avenue exit. Her 4-month-old baby was still in the car when she was hit by a red SUV, authorities said.

The initial collision involved a Hyundai Elantra and a Volvo commercial vehicle in the northbound lanes of Highway 99 shortly after midnight. Ramos then stopped her vehicle in the center median adjacent to the Hyundai. As she rendered aid to the injured driver, a red SUV allegedly driven by Comazzi struck and killed her.

For months, investigators searched for the driver of the SUV who they said stopped, got out of the vehicle for a moment, then got back in and sped away.

Eight months later, there was a break in the case when an anonymous tip came in through Valley Crime Stoppers identifying Comazzi as the driver and giving the vehicle’s possible location.

Comazzi is charged with felony hit-and-run and vehicular manslaughter. It was not immediately known if he has retained an attorney who can speak on his behalf. A phone message left Wednesday by The Associated Press on a number listed for Comazzi was not immediately returned.

Surveillance Video Helps ID Suspect

Officers were able to cross-reference the tipster’s information with surveillance video from the crash area.

Adventist Health confirmed to ABC30 in a statement that Comazzi is on its medical staff, but offered no further details.

Ramos’ loved ones urged people to submit any information they may have about any crime anonymously through Crimestoppers and said they are heartbroken that the other driver didn’t express the same compassion she did that night.

“It should be in human nature to stop and help someone, just like it was in her nature,” said Cynthia Ramos, her sister-in-law. “She could have easily stayed in her car. She went ahead and did what she loved to do, which was serve and help as a nurse.”

(GV Wire contributed to this report.)