SAN DIEGO -- A 22-year veteran San Diego police officer whose police dog died when he left it in a hot car with the windows rolled up tearfully apologized Friday, one day after he was placed on three years probation for causing the animal's death.

"I accept full responsibility for what I let happen to my friend, my partner, my family member, my police dog, Forrest," Paul Hubka said, wiping tears from his eyes as he spoke to a throng of reporters at the San Diego Police Officers Association headquarters.

"I had made a terrible mistake -- one that I will live with the rest of my life."

Hubka left Forrest, a 5-year-old Belgian Malinois, in his car in the driveway of his Alpine home on June 20. Investigators determined that Forrest may have been in the vehicle with the windows rolled up for as long as seven hours on a day in which the high temperature in the East County was well over 100 degrees. The dog succumbed to heat stroke.

Through his attorney, Hubka pleaded no contest Thursday to a misdemeanor count of leaving a dog in a confined vehicle causing death. He was placed on three years probation and was ordered to pay the San Diego Police Department $4,941 for Forrest, and to perform 100 hours of community service at a nonprofit organization.

In response to Forrest's death, the San Diego Police Department plans to purchase an alarm system for all the K9 vehicles so "this will never happen again," Hubka said.

The device starts the police car, turns on the air conditioning and rolls the windows down when the car reaches a certain temperature, said Bill Nemec, president of the San Diego Police Officers Association.

Hubka also established a foundation called Officer Paul's Vision to raise awareness about the danger of leaving dogs in cars on hot days, according to his brother, Mark.

Mark Hubka called Forrest's death an accident and said the foundation hopes to prevent similar animal deaths by raising funds for K-9 units unable to pay for the alarm system.

Paul Hubka said he did not have any excuses for his actions, but felt "morally compelled" to explain Forrest's death. He said he had just returned from an overnight shift June 20 with Forrest in the back seat. He said he did not realize it at the time, but he was both physically and mentally exhausted after working 21 of the previous 22 days.

He said he became distracted while trying to find his other dog, Sammy, and get him into the house.

"Putting Sammy inside normally signified that I needed to take Forrest out of my patrol car to put him in his kennel," Hubka said. "In my fatigue, I simply forgot that Forrest remained in the car."

He said he went to bed and did not wake up until several hours later.

"I honestly thought that I had followed my normal steps," Hubka said. "Shortly after I awoke I realized what had happened."

Nemec said the San Diego police officers will help Hubka pay his legal fees. He also said Hubka has received donations from the community to help pay for the nearly $5,000 fine.