A federal appeals court on Tuesday upheld the death sentence of a former Peninsula police officer convicted of murdering six people in his Burlingame warehouse during the early 1980s.

In a unanimous ruling, the 9th U.S. Circuit Court of Appeals rejected Anthony "Jack" Sully's bid to overturn his convictions and death sentence, giving him few remaining legal options to avoid execution if at some point California resumes lethal injections at San Quentin.

A San Mateo County jury in 1986 found Sully guilty of murdering five women and a man in 1983, carrying out the murders in an electrical supply warehouse where his victims, most of them prostitutes, were beaten, stabbed and shot in drug-fueled crimes. Three of the bodies were later found stuffed into barrels dumped in San Francisco's Golden Gate Park.

The appeals court rejected Sully's arguments that his trial was tainted by an ineffective defense, including a failure to present evidence of his mental disorders, calling the evidence at his penalty phase "staggering."

Sully, a police officer from 1966 to 1974, maintained at his sentencing that he did not get a fair trial, telling the judge, "I am not a monster, not a maniac, not subhuman," according to news accounts at the time.

Sully can ask the 9th Circuit to reconsider the appeal with an 11-judge panel, or petition the U.S. Supreme Court. But he may face long odds -- the opinion was written by Judge Sidney Thomas and joined by Judge Marsha Berzon, two of the 9th Circuit's more liberal judges who are ordinarily receptive to the legal arguments of death row inmates.

Even if Sully's further appeals fail, California is still years away from carrying out an execution as a result of ongoing legal challenges to its lethal injection procedures.

Howard Mintz covers legal affairs. Contact him at 408-286-0236 or follow him at Twitter.com/hmintz