BLOUNTVILLE, Tenn.-Former priest William Casey was found guilty Thursday in Sullivan County Criminal Court of first-degree sexual misconduct and two counts of aggravated rape.

He was taken into custody immediately and is being held without bond pending a July 22 sentencing hearing.

The verdict was delivered at 1 p.m. The charges alleged Casey, 77, of 740 Shakerag Road, Greeneville, Tenn., began to sexually abuse a young altar boy shortly after becoming priest of St. Dominic's Catholic Church in Kingsport in the 1970s.

Sullivan County District Attorney Barry Staubus called the case "one of the most emotionally draining" that he's ever handled, but said he believed the victim, Warren Tucker, now 46, finally has been "vindicated" after 35 years.

Tucker could not be reached for comment after the trial. Instead, Cal Pfeiffer, a representative of the Survivors Network of those Abused by Priests - the nonprofit group that first encouraged Tucker to go to police - offered comment on his behalf.

"He's not happy that this whole thing began, or that he had to go through the trial. He's relieved that it's over, and he's gotten some justice," Pfeiffer said.

Pfeiffer said group members hope the verdict gives "hope" to those who are "holding it inside like [Tucker] had for so many years" and shows them that they can come forward and should not be "hindered" by the statute of limitations.

Bishop Richard Stika of the Diocese of Knoxville said in a news release Thursday afternoon that the diocese had supported Tucker's efforts to seek justice against Casey from the time he reported "this horrible crime" to them.

"We are brokenhearted at the pain and tragedy Mr. Tucker has experienced over the past years, and we sincerely hope that today's verdict will bring some healing to him," Stika stated.

Stika also said the diocese had taken steps to identify and offer assistance to "any other possible victims" in the areas where Casey had served, beginning immediately after Tucker came to them.

Staubus declined to comment on what Casey's punishment might be. He said his focus thus far had been on getting a conviction.

He said officials will have to research what laws were in effect in the late 1970s and early '80s before determining an appropriate sentence.

Casey was indicted in Sullivan County on Aug. 31, 2010. He already has pleaded guilty to a similar offense committed against Tucker in McDowell County, N.C., and has additional charges involving Tucker pending in Scott County, Va.

Tucker testified Casey raped him twice - once when he was 13 and once when he was 14 - in the priest's bedroom in the rectory basement, and performed oral sex on him in his mother's trailer shortly before his 15th birthday, with Tucker saying he "felt obligated" to reciprocate the act. He described feeling powerless to resist a man he believed to be "representative of God on earth."

He described either seeing Casey or being left in his care "almost daily" because his divorced mother worked seven days a week and attended nursing school.

An only child, he said he had considered Casey a father figure, and his mother allowed Casey to take him on several overnight trips, during which he and Casey slept in the same bed. He said Casey told him he was "special" and that they had a "special love together."

Stika told the jury that a "suspension decree" was issued when Casey admitted credibility to Tucker's allegations. That decree "permanently suspended" Casey from the ministry, removed his priestly faculties, stripped him of the title "father," and prohibited him from dressing, acting or presenting himself as a priest.