By Dave Warner

PHILADELPHIA (Reuters) - A full autopsy for Cardinal Anthony Bevilacqua, a key witness in a Catholic Church sex abuse trial who died last month, is unwarranted, the coroner examining the death said on Saturday.

Bevilacqua, the retired archbishop of Philadelphia, died at age 88 on January 31, the day after a judge ruled he was competent to testify in an upcoming sex abuse trial involving clerics and a schoolteacher.

Montgomery County District Attorney Risa Vetri Ferman told reporters on Friday she had asked Coroner Walter Hofman to make a determination about the death, noting that it had come soon after the judge's ruling.

Hofman told Reuters that he had spoken to Bevilacqua's doctor the night of his death "and we felt very confident that this was not anything we need to look into further."

He added: "He was not a healthy man. He had significant pre-existing disease."

Church officials had said Bevilacqua was suffering from dementia and cancer. He died at Montgomery County's St. Charles Borromeo Seminary, the home of Philadelphia archbishops in suburban Philadelphia.

Hofman said he had drawn bodily fluids from Bevilacqua to determine if there were abnormal levels of medication. Results of tests are expected at the end of the month.

Jury selection is set to begin in the sex abuse case this month, with the trial set for March. Two priests, a former priest and a former archdiocese schoolteacher are charged with sexually abusing children.

Monsignor William Lynn, who had been secretary of the clergy during Bevilacqua's time as archbishop from 1987 to 1998 also is charged with child endangerment.

(Reporting By Dave Warner; Editing by Ian Simpson and David Bailey)