The scene that greeted police when they entered Forrest Henderson's Greenway Plaza-area apartment on Sept. 11, 1988, was grisly. Blood smeared bedroom walls, doors and curtains. The bodies of Henderson and his house guest, Richard Alan Wrotenbery, had been slashed, stabbed and bludgeoned with an iron pipe. The killer left a bloody handprint on the doorknob.

The killings rocked the genteel worlds of Houston Grand Opera, where both men performed as tenors, and Deer Park Elementary School, where Wrotenbery, the recently divorced father of a 1-year-old daughter, taught music.

A day after the murders, police spotted Henderson's stolen car traveling more than 90 mph on a Houston freeway and gave chase. When the vehicle crashed, the driver dashed into a nearby apartment complex to make good his escape.

For seven years the investigation stagnated. Then, in 1995, sheriff's deputies using sophisticated new fingerprint technology linked a bloody print from Henderson's apartment to Derrick Jackson, a Houston man serving 12 years for aggravated robbery. Jackson denied any involvement but was convicted of the double-murder in 1998.

'I'm getting framed'

Jackson is to be executed Tuesday, becoming the 15th killer put to death in Texas this year. Houston lawyers last week were reviewing the case but were uncertain if they would find grounds for further appeals.

"It's obvious I'm getting framed," Jackson said in a recent death row interview. "I'm not your bad guy. People who know me know I'm a good guy."

Police described Jackson as a predator who preyed on patrons of Montrose gay bars.

The tenors' friends said Wrotenbery lived in his friend's apartment while Henderson was on an overseas tour with the opera. When Henderson returned, the recently divorced Wrotenbery continued to occupy the residence until he could find a home of his own.

Before their murders, the men, both 31, attended a practice session for a performance of Bizet's Carmen at the opera's downtown headquarters.

Afterward, Wrotenbery returned to the apartment while Henderson visited local bars.

While there, Henderson met Jackson. "He just picked up the wrong person and brought him back to the house," Houston homicide Sgt. D.D. Shirley said after Jackson's arrest.

Henderson's next-door neighbor told police he heard loud music coming from the apartment late on Sept. 10. Then, about 4:45 a.m. the next day, a man in the apartment screamed, "Oh my God. No. No."

Henderson's nude body later was found face-down on his bed. He repeatedly had been stabbed and suffered a 6-inch skull fracture. Wrotenbery was found on the floor of a second bedroom with his throat slashed.

Wrotenbery's father, Carl Wrotenbery of Fort Worth, said the impact of his son's death will "go with me to my grave."

The elder Wrotenbery, a retired library director at Fort Worth's Southwestern Baptist Theological Seminary, said he is ambivalent about capital punishment. "When you come to the personal aspect of it, pure logic says for someone to do a crime of this nature, unprovoked — Alan was in the wrong place at the wrong time - it's hard for me to think the death penalty is unjustified."

Wrotenbery said he plans to witness the execution. "I've made my reservation," he said. "I feel like it's my duty as a father and head of the clan. I feel a responsibility to be there and see this done for other family members who, though they may have strong feelings, won't be able. I have no real desire to be there. I don't expect to feel anything different. It's just an unpleasant duty."

Crime-lab problems

Wrotenbery said the case, marked by false investigative starts and long delays, was hard on his family.

Years after Jackson's conviction, the way police handled the case was criticized by Michael Bromwich, the independent investigator hired to review operations of the department's troubled crime lab.

In his 2007 report, Brom-wich found that a technician apparently manipulated lab findings to bolster the case against detectives' prime suspect of the moment.

When an early suspect had Type O blood, Bromwich wrote, the employee neglected to report that Type B blood was found on an apartment door. Only when a charge was lodged against Jackson, who has Type B blood, was the fact added to the report.

In his death row interview, Jackson challenged those fingerprint findings and blasted a series of defense lawyers who, he said, "helped me get down to the execution chamber."

"I don't stay up at night and have nightmares," Jackson said. "I pray for myself. I hate the fact that I'm being blamed and will be killed, but it's more sadness than hate."

allan.turner@chron.com