Marrone, now a Pentagon lawyer, acknowledged that he spent more than 80 percent of his time as a young, ambitious senate aide in the late 1990s serving as a de factor general contractor on the mansion renovation project. He hired plumbers, electricians, painters, landscapers and decorators, and even found a company in California to replace locks on the period doors, he said.
Fumo and an aide, Ruth Arnao, are charged with defrauding the state Senate, a nonprofit group run by Fumo loyalists and a maritime museum of more than $3.5 million. The trial is expected to last several months.
In just one example of the work he said he did on state time, the bespectacled, husky ex-football player described his efforts to spare Fumo the annoyance of a neighbor's barking dog.
Marrone and his colleagues tried calling a city police captain and a Fumo ally on city council about the dog. He finally installed an outdoor camera to try to capture the dog barking at odd hours "so I can nail (the neighbor) once and for all," as he wrote in an e-mail to Marrone.
"Every week we'd be dealing with the barking dog," Marrone said. "He did not like the dog. I guess it was annoying to him."
Marrone is expected to be on the stand for several days. He became a key government witness in 2004 when prosecutors investigating Fumo's alleged fraud of the South Philadelphia nonprofit group contacted Marrone - who by then had had a falling-out with Fumo and married his daughter Nicole.
Marrone said he debated whether to cooperate, but over six weeks concluded that, as a lawyer and former prosecutor, he had a duty to do so.
"I really didn't have a choice," he said, as his parents, wife and brother, a Roman Catholic priest, listened in the court room.
Marrone apparently surprised prosecutors with a cache of e-mails from his Senate tenure, many about the renovation work. The profanity-laced e-mails paint Fumo, a multimillionaire banker and lawyer, as a hard-driving boss obsessed with the smallest of details.
Marrone saved the e-mails - including more than 100 being entered in evidence - at his home when he left Fumo's employ in 2002.
"It's unfortunate, but I knew this day would come and I would be sitting here," said Marrone, who said he feared Fumo would then "try to say things that were not true."
Later in the day, Marrone told jurors he did considerable campaign work on Senate time, for both Fumo and Democratic candidates Fumo supported, including U.S. Sen. Robert Casey in his failed 2002 bid for the gubernatorial nomination.
Defense lawyer Dennis Cogan, who is expected to cross-examine Marrone later in the week, suggested in opening statements that Fumo's staff may have worked long hours trying to please the boss, but only after putting in a full day for the Senate. Fumo staffers "broke their necks working for the state of Pennsylvania," Cogan told the mostly female jury.
But Marrone's e-mail messages appear to support his contention that he spent most of his Senate work days over an 18-month period on the house renovations.
The jury learned Monday that Fumo's second wife, Jane, moved out of the mansion before the renovations were finished. They later divorced.
But it remains unclear how much detail jurors will hear about the veteran senator's estrangement from Marrone and his eldest daughter. Fumo did not attend their wedding and has never seen their two young children, his only grandchildren. And after being estranged for at least five years, he walked past Nicole and her in-laws in the courthouse last week without a passing glance.