He calls his victims the "Eleven that went to Heaven."

Edward Harold Bell, admitted sex offender, convicted murderer and self-described serial killer, has given multiple chilling confessions from his locked prison cell of abducting and slaying teenage and adolescent girls in the 1970s, describing crimes even now unsolved.

In disturbing letters sent to Harris and Galveston county prosecutors in 1998 - but kept secret for 13 years - Bell claimed to have killed seven girls, including two Galveston 15-year-olds shot as they stood tied up and half naked in the chilly waters of Turner Bayou, according to excerpts and descriptions of Bell's letters obtained by the Houston Chronicle.

In July and September, in exclusive interviews, Bell, now gaunt and pasty-faced at 72, told a Chronicle reporter the tally of lives was not just seven, but 11, the "Eleven that went to Heaven."

Bell claims a brainwashing "program" forced him to "be a flasher," to "rape girls" and ultimately to kill.

Related: Documentary Series reexamines 70s serial killings in the Houston/Galveston area

Several senior investigators familiar with Bell's letters of confessions told the Chronicle they have long believed he committed multiple murders and found evidence to corroborate his claims. But probes stalled.

Galveston prosecutors refused to present Bell's written confessions to a grand jury. Harris County prosecutors never investigated the claims and subsequently lost the letters. And Bell refused to cooperate with police. Several investigators said not enough effort was made in 1998 to re-investigate the cases.

One former Galveston DA, Kurt Sistrunk, told the Chronicle, "I didn't believe we had sufficient evidence that we could proceed to grand jury with, and without getting into specifics, that's the decision that had to be made, no matter the temptations to proceed otherwise ... It wasn't for a lack of effort."

Saw her son die

Bell is serving 70 years for the 1978 murder of Larry Dickens, a Marine who confronted Bell after he exited his red and white GMC pickup naked from the waist down and began masturbating in front of a group of girls in Pasadena. Dickens' mother watched from her house as Bell shot her son four times, emptying his pistol, then retrieved a rifle to administer a coup de grace.

The "program" killings, as Bell calls them, began well before then. The victims were young girls from Houston, Galveston, Webster and Dickinson. The murders came in waves: five in 1971 and six more from about 1974 to 1977. Six teens, he adds, were murdered in pairs.

Bell named three victims from 1971: Debbie Ackerman and Maria Johnson, 15-year-old Galveston surfer girls and experienced water skiers who disappeared after hitchhiking, and Colette Anise Wilson, 13, who never arrived home near Alvin after attending a summer band camp.

All three cases remain unsolved, though Brazoria County Sheriff's officials long theorized Wilson and another girl were murdered by a convict killed in a 1972 jail escape. Wilson's bones were found in a reservoir mingled with those of a missing Houston girl, Gloria Ann Gonzales, 19.

In 1998, Bell described murdering Ackerman and Johnson in letters written from a maximum security cell in Huntsville 17 years after the crime: "I was 'Brainwashed' into killing Deby (sic) Ackerman and Maria Johnson in November 1971," Bell wrote. He detailed how he shot them and described the remote bridge where the bodies were recovered.

Ackerman and Johnson were last seen accepting a ride near an island ice cream shop from a man driving a white van. Their abductor tied them up, stripped them from the waist down and left their bodies in the bayou, records show.

Bell owned a white 1971 Ford Van, lived in an apartment in a sprawling beach house along Offatts Bayou, and had invested in a surf shop that both girls visited before their deaths, according to documents and interviews. In fact, Bell was arrested in the van in February 1972, after flashing a 15-year-old on a sales trip to Greta, La. Bell repainted the van and it later burned, Bell and others said.

Bell identified another of his victims as a reddish-blond Houston teen named "Pitchford," kidnapped near Gulfgate Mall. Harris County medical examiner's records and newspaper archives show Kimberly Rae Pitchford, a 16-year-old who lived near Hobby airport, never returned home after taking a driver's education class at Frank Dobie High School in Houston. Her body was found in a thicket in Brazoria County in January 1973.

Bell claims not to know the names of other girls. In some cases he remembers the color of their hair. The 1971 murders included Ackerman, Johnson, Wilson and two Webster girls Bell does not name.

Just three months before Ackerman and Johnson disappeared from Galveston Island, so did two Webster 14-year-olds named Sharon Shaw and Rhonda Renee Johnson. All four girls hung out at a popular water ski school on Offatts Bayou near Bell's apartment.

Related: Some suspect serial killer in 1971 Galveston deaths - did the wrong man die in prison for 1971 slayings?

Was traveling salesman

Another six killings occurred in the mid to late 1970s, including Pitchford and two girls in Dickinson, Bell told the Chronicle.

Deed records show Bell owned a rural pasture a few minutes' drive from the Dickinson store where two middle school students, Georgia Geer, 14, and Brooks Bracewell, 12, were last seen in 1974. Their bones were recovered in a bayou in 1976 and identified in 1981.

Related: Two girls went missing in 1974 - why didn't police investigate?

Of the remaining three, one was killed after hitchhiking near Highway 2004 in Santa Fe, Bell says, and two more came from Houston, one brunette and another red-haired.

"If you could get me immunity from prosecution of any kind, I could lay a lot stuff on you and I will," Bell told the newspaper.

Known as "Butch" to family and friends, Bell's early life seemed normal - even exemplary. He was a Boy Scout, graduated from Columbus (Texas) High School and earned a physical education degree from Texas A&M, where he played in the Aggie Band.

After graduation, he worked as a licensed diver and met and married his first wife in San Marcos. The two moved to West Texas and had three children. For years, Bell made his living as a traveling pharmaceutical salesman based in Plainview and later sold Terlingua ranchland out of an office in downtown Houston.

For most of his life, Bell claims he did not know what compelled him to do evil. In the 12 years or more before he was arrested for the Marine's murder, Bell actively trolled for girls and exposed himself across Texas and Louisiana in vehicles he often altered and swapped, records show.

Bell was stopped by police at least a dozen times for masturbating and flashing girls in Lubbock, Plainview, Bacliff, Houston, Pasadena and Gretna, La., between 1966 and 1978, according to records and Bell's own admissions.

His pattern: Drive around until he found unaccompanied adolescent girls, strip down below the waist and masturbate as they watched. He often targeted girls in pairs. Most victims were 11 to 16 years old. He repeatedly avoided arrest and prosecution.

He bragged to friends that he could talk his way out of anything. In an interview, Bell's sister-in-law, Janice Bell, described Bell as a "great con man" and a "Texan big mouth … he bragged a lot, he was always right." She called him a liar and a killer who kept secrets.

Bell blamed the crimes and carnage in his life on a systemic program of abuse, lies and brainwashing begun by his father, a well-connected gauger who frequently moved his family to small oil field camps and towns within an 85-mile radius of Houston.

"My father thought if he beat you real bad, it would send chemicals into your bloodstream," Bell said.

Bell lists former scoutmasters, a cousin and his three ex-wives as part of "the program." He mixes accounts of the damage wrought by others with admissions of uncontrollable cravings for sex with younger women.

"One thing they wanted me to do for sure was rape a girl," he said. "They wanted me to rape girls and rob banks and rob people. My father tried to brainwash me into killing myself."

More arrests

Flashing was phase one. Bell's first documented incident, records show, occurred in 1966, when he was stopped for exposing himself to girls in the tiny town of Sudan an hour west of Plainview, and ended up in Big Spring state mental hospital, according to Bell and records. The treatment didn't take.

Three years later, Bell, still married to his first wife and working as a traveling salesman, got arrested again - twice - for exposing himself to girls in two different West Texas towns. He avoided prosecution by agreeing to report to another in-patient treatment program for so-called perversion, and soon arrived at the University of Texas Medical Branch mental hospital, Jennie Sealy in Galveston. His marriage ended, as did contact with his children.

Bell turned his time in the mental ward into opportunity to romance underaged patients. He "dated" one 16-year-old but says he didn't "make love" to her because "I was already in enough trouble with the law ... I didn't want statutory rape on top of the flasher charge."

Next, he seduced a 17-year-old psychiatric patient in Room 417, according to Bell. A few months after his release, he married her. Bell was 31. In 1970, Bell and his new wife rented an apartment in the beach house along Offatts Bayou.

Through a mutual friend, Bell met Doug Pruns, a surfer who made custom boards and owned a shop on Avenue S.

Bell became a silent partner in a dive business at Doug's Surf Shop. In an interview, Pruns said he once visited acreage near Dickinson where Bell kept horses, raccoons, myriad critters and a travel trailer painted to look like a red caboose. Pruns considered Bell a creepy weirdo, but knew little of his life.

In 1974, Bell was busted twice in Galveston County. In April, he exposed himself to two girls on a road near Bacliff and pursued them in a Volkswagen rental as they ran. He next was arrested in the rape of a Jennie Sealy mental patient whom he says he met outside the hospital. Both cases were dropped.

In 1978, he trolled for girls in suburban Pasadena in a red and white GMC pickup, in which he kept a .22-caliber pistol, an M-1 carbine and porn magazines, Harris County records show. On June 26, he exposed himself to two girls riding bikes, aged 11 and 12. Five weeks later, he stepped out of the pickup wearing only a pair of black boots and masturbated before five Pasadena girls practicing cheer leading.

The next time he displayed himself to Pasadena girls, on Aug. 24, 1978, Bell came face to face with Dickens. Bell killed him for interrupting.

Bell was arrested and posted a $125,000 bond. He jumped bail. For the next 14 years, Bell roamed coastal towns in Mexico and Central America, guiding dive trips and living aboard a sailboat. He assumed the identity of a dead cousin named Cecil Boyd and told people to call him "Wally." He panned for gold, married for a third time and entertained visiting Texans on dive trips, according to records and interviews with Larry Boucher, a retired investigator for the Harris County District Attorney's Office who tracked Bell for years.

Named Texas' most wanted fugitive in the 1980s, Bell was featured on the TV series Unsolved Mysteries and captured by Panamanian police at a yacht club in 1992. He went to prison the next year.

Boucher read Bell's confessions and says he's an unpunished serial killer. He remembers Bell's rants about bees invading his locked cell and his admissions to killing girls in a letter that's been lost.

"My gut feeling is that he is responsible," Boucher told the Chronicle.

'70s disappearances

Forty-year-old investigative files reviewed by the Chronicle document many agencies' unsuccessful attempts to solve the disappearances of teenage girls in the 1970s - a murderous decade that ended with suspicions one or more killers escaped prosecution.

So many teen girls turned up dead in 1971 that the Harris County sheriff called more than 60 officers from across Texas to a secret summit to coordinate a response. A murderer, or murderers, seemed to cross city and county boundaries to dump victims in remote, roadless areas.

Over time, several serial killer suspects were developed. Most died long ago, leaving nearly all the murders unsolved. Until Bell's confession letters arrived in 1998, he'd never been investigated.

Those letters electrified Deril Oliver, a retired Texas City detective who helped pull the bodies of Ackerman and Johnson from Turner Bayou. Oliver tried to interview Bell in prison. He said others were too quick to dismiss Bell as a publicity-seeking kook.

"Bell was the closest thing to a real suspect that we ever had," Oliver said. "I think they let it go too soon."

Among investigators convinced of Bell's guilt is Alfred Paige, a Galveston police officer who investigated Bell in between new homicide cases from 2005 to 2010. Paige, who heard about 1970s teen murders as a boy growing up in Central Texas, found scattered relatives and friends, including witnesses who'd never been interviewed, and documents that tied Bell to the unsolved crimes. He pushed without success for Galveston DA Sistrunk to use the letters and other evidence to indict Bell.

"The investigation certainly remains open," said Sistrunk, who now works for the Brazoria County prosecutors office, "and what we can count on is that because of the work of (Paige), those before him, and other area law enforcement agencies that may become even more involved, we will reach a point in time where sufficient evidence will be made available to law enforcement that will let the case proceed to a grand jury for justice to be served."

If Bell's confessions are true, only he holds answers long sought by the families of victims.

"It makes it hard that we don't know if this Bell guy is a nut or if he's telling the truth," said Dotti Walker, the aunt of murdered Webster teenager Sharon Shaw, who disappeared with her friend only a few months after Ackerman and Johnson. "As bad and as mean as he is, he could be telling the truth because of his conscience ... Not knowing is heartbreaking."

lise.olsen@chron.com