The former head of the state Trial Court system, a pivotal witness in the public corruption trial of former Probation Department officials, told a federal jury Tuesday that he began to spar with Probation Commissioner John J. O’Brien soon after taking office in 2003, when he began to question some of O’Brien’s hiring practices.
Robert A. Mulligan, 70, was the head of the Trial Court system that oversaw the Probation Department when O’Brien was in charge, and prosecutors hope to use his testimony to show that he was duped by O’Brien’s fraudulent hiring process, testimony that goes to the heart of the federal case against O’Brien and two codefendants.
But defense attorneys plan to argue that Mulligan knew that patronage hiring was widespread in Beacon Hill and that even judges participated in it by recommending probation officers and court officers for jobs.
Mulligan is expected to undergo intense questioning by both prosecutors and defense attorneys when he returns to the stand Wednesday.
Mulligan took the stand only briefly Tuesday, and prosecutors sought to show the tension between O’Brien and Mulligan that started to brew just after Mulligan took office.
Though Mulligan still had to sign off on appointments, a 2001 change in state law had given O’Brien hiring authority over probation employees, and O’Brien had sought to have judges completely removed from the process. Mulligan refused.
“It seemed everything between us became a contest,” said Mulligan, who retired last year as chief justice for administration and management for the state courts.
“Meetings were intense. They were difficult. . . . It became oppositional.”
Prosecutors say that O’Brien and his deputies Elizabeth Tavares and William Burke III sought to curry favor with state legislators by directing jobs their way, in exchange for regular budget increases for their department.
The prosecutors called the jobs “political currency” that helped O’Brien build his own political empire.
Defense lawyers say that their clients did nothing illegal, arguing that the hiring arrangements were patronage typical of Beacon Hill politics. But prosecutors say they committed fraud by creating an organized scheme and making applicants go through a bogus hiring process.
O’Brien is also accused of falsely certifying to judges, specifically Mulligan, that he followed proper policies and procedures in making appointments
If convicted, the defendants face up to 20 years in prison on some charges, including mail fraud and racketeering.
The trial began with opening statements on May 8, and Mulligan was the 45th witness to take the stand over 29 full days of testimony. He is slated to return to the stand Wednesday.
At one point, according to his testimony Tuesday, O’Brien proposed interviewing 3,800 candidates for 52 positions, which Mulligan called a waste of the judges’ time and a ploy to discourage them from participating in the hiring process.
He said he told O’Brien it was an “attempt to fulfill your own prophecy that judges would not want to be involved.”
Mulligan testified that his human resources staff also started to flag some of O’Brien’s questionable hires. One candidate for an assistant chief position in Fall River District Court in 2005 was offered the job even though she did not make an initial list of eight finalists.
That candidate received the job over an applicant who had been working in the Fall River District Court for more than a decade and who was ranked highest by each member of the screening panel.
In another case, in 2006, Mulligan questioned one of O’Brien’s deputies, Pat Walsh, in a private meeting about her generous scoring of a candidate in a final hiring round, even though the candidate had scored poorly in an earlier screening.
Mulligan said that Walsh’s score sheet indicated the candidate was a “genius” in probation matters, though he had earlier had a “dearth of knowledge” about the department.
Walsh refused to admit any wrongdoing in the hiring, Mulligan said.
O’Brien later wrote a letter to Mulligan opposing the “unprecedented interrogation” of his deputy, and he threatened to ask the Supreme Judicial Court to clarify his hiring authority.
Mulligan’s testimony came after one of O’Brien’s top aides told the jury that he and O’Brien collaborated with state Representative Robert DeLeo’s office to offer probation jobs to friends of legislators whose support DeLeo was seeking when he was running for House speaker.
Friends of several state representatives, including state Representative Harold P. Naughton Jr. and then-Representative Robert Rice, both Democrats, were offered jobs without being interviewed.
The representatives supported DeLeo, who was elected House speaker in 2009.
O’Brien “told me they were trying to gather support for chairman DeLeo,” Edward Ryan, O’Brien’s former legislative aide, told jurors.
Ryan said he met with one of DeLeo’s aides, Lenny Mirasolo, and “he clearly indicated to me he was trying to get Representative Naughton and Representative Rice to vote for DeLeo in the speaker’s race.”
O’Brien, “would talk about the number of votes,” Ryan added.
“They were getting close in getting commitments from legislators in getting a victory for chairman DeLeo.”
DeLeo has repeatedly denied any wrongdoing.Milton J. Valencia can be reached at mvalencia@
globe.com. Follow him on Twitter @miltonvalencia.