A driver is being held without bail on a murder charge after police said he intentionally ran down a prominent art collector and his dog in Boston over the weekend.

John Axelrod, 79, of Boston, was walking his dog on the Commonwealth Avenue mall at Hereford Street Saturday morning when he was hit by a car. The driver didn't stop, according to investigators.

Axelrod was rushed to a hospital where he died. His dog, a terrier named Tale, also died. The car that hit them was later found in nearby Brookline, Massachusetts.

The accused driver, 42-year-old William Haney of Boston, turned himself in to the Brookline Police. He's now charged with first-degree murder and cruelty to animals. 

Haney pleaded not guilty to the charges at his arraignment in Boston Municipal Court Monday afternoon. He was ordered held without bail and sent to Bridgewater State Hospital for a mental health evaluation. His next hearing is scheduled for January 23. 

Prosecutor Ursula Knight said Haney left his home on Marlborough Street and drove his Toyota SUV in the direction of the Commonwealth mall Saturday. He stopped to ask a passerby if they had seen a man in a red coat walking a dog. Investigators said he also used a "derogatory term" before he appeared to drive onto the mall and speed up directly into Axelrod and his dog Tale. A woman who was walking with Axelrod and his dog at the time told prosecutors that Haney deliberately aimed the car at Axelrod and spared her. Witnesses said they heard a "loud bang" and the "sounds of a yelping dog" from the crash.

Haney was seen shortly after stopping at a Dunkin' on Beacon Street, where he removed the dog's leash from his tire and threw it into a garbage can, according to Knight.

Authorities said Haney then brought his car to a shop to get the front damage fixed, but was denied service. Haney also allegedly asked to keep his car there for a few days, but was also denied. Knight said that he then left the SUV at Thorndike and Harvard Street in Brookline. Haney then met up with his brother, and they walked into the Brookline police headquarters, according to investigators. His brother told police that Haney had been in an accident.

Haney's attorney, Keith Halpern, said his client has a history of mental health issues, including schizophrenia, and had recently changed his medication back in August. Haney's brother told a court psychologist, Dr. Heather Jackson, that Haney has had a hard time figuring out between "reality and fantasy" since the medication change. Dr. Jackson said it appeared Haney was hearing auditory hallucinations during her evaluation and explained that he didn't know what he was being charged with.

"He's really been fighting delusions and psychosis for months at this point," Halpern said.   

Halpern claimed Haney had no connection to Axelrod. 

Remembering John Axelrod

Axelrod was a well-known art collector and a major supporter of the Museum of Fine Arts.

In a statement, the MFA said he was a "generous supporter and passionate advocate for underrepresented artists."

"John had been a part of the MFA family since the 1980s. His legacy will live on at the Museum through the John Axelrod Collection," the museum said. 

Mildred Gonzalez, a friend and relative of Axelrod's partner, said that his passing will leave a giant hole in their family. 

"I'm not sure who we're going to spend the holidays with anymore, any special occasions. He's going to be missing," Gonzalez said. "John is an amazing human being. He didn't deserve this. No one deserved this."