PUEBLO, Colo. -

An admitted kitten killer was sentenced to two years and three months in prison Monday.

Robert Heckmann, 26, pleaded guilty to videotaping himself torturing and killing a 13-week-old kitten named Loki.

Both the prosecution and defense wanted District Judge Victor Reyes to sentence Heckmann to probation, arguing that it would better allow Heckmann to receive mental health treatment.

But Reyes sentenced Heckmann to nearly the maximum sentence, which was three years. Reyes said he found aggravating circumstances that factored into his decision, including Heckmann's previous criminal history. In 2006, Heckmann reportedly used as a bat as a weapon. In addition, Reyes told Heckmann he previously violated the terms of a four-year-probation.

"Until you're ready to actually change, then nothing will happen," Reyes told Heckmann.

Heckmann apologized for killing Loki. "I know what I did was wrong and I'm very, deeply sorry for it. There's no justification whatsoever. There's no reasoning behind it."

Reyes told Heckmann, "I don't think you're an evil man." He then added, "I think you've done a very cruel thing."

Loki's owner, Steven Malcolmson, said the sentencing wasn't enough. He and Heckmann were friends for more than three years. "There's no words for it at all, just sad. Animals are an innocent life," he said. "It's, in my opinion, a cowardly crime."

Members of the group, Justice for Loki, said they were pleased with the sentencing. "Two years and three months is much more than what we were expecting," said Darla Scheuerman, a spokesperson for the group.

Investigators with the Humane Society of the Pikes Peak Region say in January Heckmann sent his then-girlfriend text messages, describing how euphoric he felt after killing Loki. Soon after Heckmann pleaded guilty, but Reyes rejected Heckmann's first plea deal because Heckmann went on KRDO NewsChannel 13 and said he reluctantly agreed to plead guilty. Heckmann claimed he was partly responsible but that others were also involved in Loki's death.

In May, Heckmann pleaded guilty, a second time. This time he told Reyes, "I strangled a cat."