Hearing On 1990s Boston Cop Killing

A half-dozen Boston police detectives could be called as witnesses Tuesday in a hearing to determine whether a man convicted of killing a Boston cop 21 years ago should be given a new trial.

The lawyer for Sean Ellis is trying to show that police ignored important evidence in the murder of Det. John Mulligan.

A detective who testified Monday said no one followed up on scores of calls to a police tip line.

Ellis attorney Rosemary Scapicchio says that shows investigators focused only on her client.

“They built their entire investigation around proving that that individual [Ellis] did it, to the exclusion of all the other evidence,” she said.

Prosecutors deny any exculpatory evidence was withheld in Ellis’ previous trials.