Whitey Bulger Trial: More victims' relatives to take the stand Friday after an emotional day of testimony

(CBS/AP) BOSTON - Donald Milano remembered fondly the day his big brother showed him his brand new Mercedes Benz.

"He was quite proud of it," Milano recalled Thursday.

The next day, Michael Milano was dead, gunned down by a hitman who worked with James "Whitey" Bulger, prosecutors said.

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Donald Milano was among a string of witnesses who testified at Bulger's racketeering trial about the deaths of their loved ones, allegedly at the hands of Bulger and his gang.

More relatives of victims are expected to testify Friday.

Bulger, 83, is charged with playing a role in 19 murders during the 1970s and `80s while allegedly the boss of the mostly Irish-American Winter Hill Gang. He has pleaded not guilty. His lawyers say he made millions through drugs, gambling and loan-sharking, but they say his former associates have fabricated

or exaggerated his role in the killings to get reduced sentences for their own crimes.

A woman who was a passenger in Milano's car the night he was killed in 1973 choked back tears as she recalled ducking down in the front seat when she heard a hail of gunfire.

Diane Sussman de Tennen said she was in a car driven by Michael Milano - a 30-year-old bartender - when a car pulled up to them at a stop light in Boston's North End neighborhood.

"All of a sudden, there was this noise, a continuous stream of gunfire. ... It was just nonstop," she said.

After the noise ended, she got up and saw Milano, who was leaning forward into the steering wheel.

"I looked at him and I asked him if he was OK, and I got no response," she said.

When she looked in the backseat, she saw that her boyfriend, Louis Lapiano, was seriously wounded. He spent the next 28 years as a quadriplegic before he died in 2001.

Prosecutors say Milano was killed because he was mistaken for another man who was the intended target.

Under cross-examination by Bulger's attorney, J.W. Carney Jr., Sussman de Tennen said she did not see who shot at the car.

When Carney asked if she knows who shot Milano, she declined to answer, saying it would be speculation.

"In my mind, I do know," she said. Former hit man John Martorano testified this week that he shot

Milano in a case of mistaken identity. Al "Indian Al" Notarangeli, the leader of a rival group, was the intended target.

Bulger became of the nation's most wanted fugitives after he fled Boston in 1994. Prosecutors say Bulger had secretly worked as a high-level FBI informant and provided information on members of

the rival Italian-American Mafia, once the top federal crime-fighting priority. He was captured in Santa Monica, Calif., in 2011.

Complete coverage of the Whitey Bulger case on Crimesider