In therapy sessions, the priest confessed to shocking details he'd kept hidden for years: he had molested more than 100 boys, including his 5-year-old brother, had sex with male prostitutes, and frequented gay strip clubs.

The admissions of Reverend Ruben Martinez are among nearly 2,000 pages of secret files, unsealed Wednesday, which regard priests, brothers and nuns accused of child molestation while working in the Los Angeles archdiocese.

The papers, released under the terms of a $660m settlement agreement reached in 2007, are the first glimpse at what Catholic religious orders knew about the men and women they posted. Several dozen more files are expected to be released by fall.

The documents refer to 10 priests or brothers and two nuns, all accused in civil lawsuits of molesting children; among them, the accused had 21 alleged victims between 1950 and 1980. The release included documents from the Oblates, the Marianists, the Benedictines and two orders for religious sisters.

That some files don't reflect the alleged abuse doesn't mean it didn't happen, said Ray Boucher, lead attorney for some abuse victims. "Much of this went unreported. You're talking about kids that were terrorized and frightened in so many different ways, with no place and no one to turn to."

At more than 500 pages, Martinez's file is among the most complete, and it paints a devastating picture of a troubled child who joined the priesthood to satisfy a domineering father.

The archdiocese settled eight lawsuits over Martinez's actions in 2007, but had little in its own files, though he worked in its parishes for years.

His order file, however, includes therapy notes and psychiatric evaluations, and reveals years of effort – and tens of thousands of dollars – the Oblates spent trying to cure him of his self-admitted paedophilia.

In a 1993 psychiatric report, one of several such evaluations, the priest admitted to molesting children. In the documents, Martinez says he stopped "direct sexual contact" with boys after a mother complained to a pastor in 1982, and that he stopped touching boys altogether after another complaint in 1986.

In 1991, he received five months of inpatient psychological treatment from a center in New Mexico that specialized in treating troubled priests.

Upon his release, Martinez was assigned to a tiny parish in the remote town of Westmorland, in the far southeastern corner of California. While there, he would drive miles to San Diego to pick up male prostitutes, according to his file.

He was removed from parish ministry in 1993, enrolled in a sex offender program and sent to work at the order's California headquarters in Oakland. For the rest of his career, he filled administrative roles.

Calls to his order, the US Province of the Oblates, and emails to the attorneys of the accused were not returned.

Carolina Guevara, a spokeswoman for the archdiocese, said orders are expected to make sure priests they present for ministry don't have any history of sex abuse.

One man who sued over Martinez's abuse told the Associated Press that the priest molested children in 1972.

"He would have us wrestle each other and then wrestle with him, which means we'd get down into our skivvies and he'd take pictures of us. He was always taking pictures," the man said. "I just remember the smell of the old Polaroid flash cubes. He would go through them like crazy."

The man received a settlement in 2007 from the archdiocese. Martinez was never charged criminally; most of the alleged abuses weren't reported until years later.

The man said Martinez always had a group of young boys around him and would take them to see R-rated movies. One summer day, he recalled, the priest took six boys to a local amusement park, but stopped on the way at an apartment where another man lived. Martinez and the man went inside with one of the boys and left the other five in the car for several hours. When the trio came back, the boy was sobbing and didn't stop for hours.

In 2003, Martinez was moved to the Oblates' offices in Washington DC, where he worked answering phones and in the archives. There, his files show, he was reprimanded for making jokes that offended several women and, later, for looking at sexually suggestive pictures of young boys, and for downloading a floppy disk filled with "references to topics dealing with the gay lifestyle". He also marched in a gay pride parade.

"I don't know who else has time to monitor him, or to what 'safe' place we could assign him," the Rev Charles Banks, director of personnel for the Oblates wrote in an exasperated memo in 2003.

The file shows that Martinez was sent to the Missouri retreat home for troubled priests in 2005. In a psychiatric assessment dated that same year, Martinez said he hadn't had sexual contact with a child in 23 years and had learned to control his impulses. The same report notes that at age 13, Martinez sexually molested his little brother and went on to molest "about 100 male minors" – a detail also included in several other therapy evaluations.

"It has not been easy to face what I did, to admit it and to talk about it with others," Martinez wrote to the order's provincial in 2006. "I have had to deal with depression, self-hatred, the inability and unwillingness to forgive myself, and the desire and tendency to isolate."