She actually left her home in Greencastle for Cincinnati specifically to have the abortion. She told her parents she was visiting friends in Indianapolis.
The father of the child may have been Scott Jackson or may have been Pearl's second cousin Will Wood, son of the Presiding Elder of the Methodist Episcopal church in Indiana. Wood denied having "criminal relations" with Pearl. Jackson admitted it but claimed Wood had her first. Wood helped arrange the abortion, but later testified against Jackson.
Neither Jackson nor Walling (Jackson's roommate) admitted any knowledge of Pearl's death and both were convicted on circumstantial evidence. A week before they were hanged they implicated a Kentucky Dr. (who at the time was an inmate at an insane asylum) in a partial confession.
I've just finished the second draft of a novel about Pearl Bryan's death. When I finish number three I may have something.