Brennan, 47, is among three priests, a defrocked priest, and a former parochial schoolteacher charged with sex crimes and child endangerment in a case that has rocked the Roman Catholic Archdiocese of Philadelphia and drawn national attention.
He was removed from active ministry in 2006 after his alleged victim came forward. In recommending charges against Brennan last month, the grand jury painted a disturbing picture of his behavior with minors. It also heard testimony from the priest's accuser and found him credible.
DeSipio suggested that Brennan's alleged victim, now 29 and in jail on a drug charge, had concocted the abuse story, just as he once lied to police that he had been stabbed by an intruder in his Newtown, Bucks County home.
The Inquirer is withholding the man's name because prosecutors say he was the victim of a sex crime. He could not be reached for comment.
In February 2005, court records show, the man called police to report that someone had broken into his home at 3 a.m., stabbed him in the arm and chest, and stole $675 in cash, along with prescription drugs, a watch, and a DVD player.
A detective noted that he had "several small, superficial cuts on his right arm and chest," but was otherwise uninjured. Within two days, a police investigation concluded that the man had made up the story.
His mother, who had been home at the time, told police she heard nothing, and was "suspicious" of her son's account. He had a drug problem, she said, and had recently stolen and cashed her personal checks.
Police charged him with filing a false report to law enforcement. He pleaded guilty and was sentenced to up to one year in jail.
He also was convicted of driving while under the influence of drugs in 2010.
"Not only did he make up the home invasion, he faked the corroboration by cutting himself," DeSipio said. "You have to pause and ask yourself who's saying this."
The priest, however, was the one taken to task by the grand jury.
While Brennan was a teacher at Cardinal O'Hara High School in Springfield in the early 1990s, administrators expressed concern that he was hosting parties with students and possibly serving alcohol. At one point, they banned him from taking students into closed-door meetings.
In 1995, the grand jury said, Brennan invited a 17- or 18-year-old male to live with him for several months in an archdiocesan home for learning-disabled women, where he was chaplain. When the nuns at the home questioned the arrangement, the panel said, Brennan lied and claimed the young man was his nephew.
Cardinal Anthony Bevilacqua later noted in Brennan's personnel file that he had "doubts in my mind about his honesty."
As for questions surrounding the accuser's credibility, an advocate for abuse victims said Tuesday that self-destructive or antisocial behaviors are not unusual among those sexually assaulted as children.
"Substance abuse, eating disorders, depression, anxiety, sexual problems and run-ins with the law - these can happen when you're exposed to trauma at an early age," said John Salveson, president of the Foundation to Abolish Child Sex Abuse. "Not all victims are broken people, but it has a profound effect on your well-being."
It is "patently ridiculous" to think that someone would make up charges against a priest, Salveson said. "It's a humiliating and embarrassing thing to come forward and admit these things."
For his part, Brennan told radio host Chris Stigall on WPHT-AM (1210) that he looked forward to his day in court.
"I don't want to die on the hill of public opinion."
Contact staff writer Nancy Phillips at 215-854-2254 or firstname.lastname@example.org.
Inquirer staff writer Larry King contributed to this article.