Before deciding whether to impose a death sentence on Martin Aguilar, a federal jury heard the story of his childhood.

It is a story of the “regular stuff that kids would do,” his former babysitter testified yesterday in U.S. District Court in Brooklyn, where jurors are close to beginning their deliberations. Defense attorneys seem to be pinning their hope for leniency on showing the jurors how, at some early point in Aguilar’s life, he was not so different than they were.

Aguilar, 33, now faces the death penalty following his conviction last month for a 2000 murder-for-hire. The jury is expected to begin death sentence deliberations this week. The murder of Jose Fernandez, the crime for which Aguilar was convicted, is only one of the violent acts he committed over the last 15 years, prosecutors say. Witnesses for the government testified last week that since 1991, Aguilar has stabbed a man to death with a screwdriver; shot at couples parked in cars beneath the Verrazano-Narrows Bridge; shot and robbed two Bronx drug dealers; slashed a man in the street; and, while awaiting his death penalty trial in federal custody, prosecutors say, Aguilar stabbed a handcuffed inmate with a shiv.

Now that the prosecution has rested, defense attorneys are trying to convince the jury that Aguilar’s life is not the sum of these rampages. His lawyers, attorneys Carl Herman and Louis Freeman, are pinning their hopes for leniency on Aguilar’s earliest years. Yesterday they called forward an ex-babysitter, a brother, a cousin, and Aguilar’s mother. These witnesses testified that Aguilar was a sensitive child, whose better emotional instincts were suffocated by his father.

“To me he was a really nice kid, very happy, very well spoken,” Aguilar’s summertime babysitter, Evelyn Pelaez, testified yesterday. “He had a collection of He-Man action figures. He did the regular stuff kids would do.”

Aguilar was absent for the testimony of his mother, Elizabeth Fernandez. Much of what she said yesterday detailed the abuse she said she suffered at the hands of her father until she left home at the age of 15. The jury could interpret Aguilar’s decision to excuse himself as a kind act of a son trying to save his mother unnecessary embarrassment.

In a flat and tired voice, Ms. Fernandez painstakingly detailed her son’s earliest and most innocent years. Aguilar weighed nine pounds and two ounces when he was born. He had an extra toe. His first spoken word was milk and it did not come until he was four years old. But he quickly became a talker after that, so Ms. Fernandez said she nicknamed him “Sassy,” which her husband, Edwin Aguilar, who is now dead, abhorred.

“His father didn’t like the name, it sounded too girly,” Ms. Fernandez said. She described how Aguilar’s father, Edwin, wanted her son to become tough. Edwin, Ms. Fernandez said, never passed down an opportunity to encourage Aguilar to bloody up other kids, whether the setting was in karate class or the communal stairwell of the Sunset Park, Brooklyn, building where they lived.