ON THE WORN steps of her South Philadelphia rowhouse yesterday, Gabrielle "Brie" Rockmore glanced up at rain clouds as dreary and close to breaking as her heart.

Just over a week ago, life was happy. Her beau had proposed, she was almost halfway through technical school and her 4-year-old son declared his devotion to her in orange crayon on a homemade Mother's Day card.

But instead of basking in pre-betrothal bliss, Rockmore sat yesterday crippled by unbearable heartbreak, absently rubbing the curlicued "Little Tony" tattoo inked on her forearm.

Her only child, little Anthony Elam, lies brain-dead at Children's Hospital of Philadelphia, kept alive by machines only until his organs can be harvested for donation.

Police say her 6-foot-1, 250-pound fiance, Lawrence "Lindbergh" Craig, battered the boy. They say Craig, 29, admitted he used a belt-buckle to beat the preschooler to the brink of death on Tuesday. Detectives suspect Anthony's abuser used other objects in the beating too.

But Rockmore has not taken off her engagement ring, a bauble with a gem as blue as a sunny sky.

No matter what police say, she remains unconvinced of her fiance's guilt. She attributes her skepticism to her criminal-justice studies; she's in her second semester at a local technical school, with plans to graduate by December 2009.

"I basically want to know what happened to my baby," said Rockmore, 24, adding that she never saw Craig mistreat Anthony nor noticed any previous injuries on her boy. "That's one thing I learned in criminal justice: You have to look at all aspects of the situation first. You can't just point the finger."

Rockmore started dating Craig, whom she met through a mutual friend, about a year and a half ago.

Things got serious enough that two weeks ago, Rockmore and Anthony moved from her grandmother's rowhouse on Carpenter Street near 19th into Craig's dilapidated, two-story, red-brick rowhouse, seven blocks away on Watkins Street near 19th.

The trio quickly fell into a routine, Rockmore said.

Rockmore dropped her son off at the Head Start preschool at South Philadelphia High School every morning about 8:30 a.m. and then headed to her classes. Craig picked Anthony up daily about 2 p.m. and baby-sat him for the hour or so until Rockmore's school day ended.

Last Tuesday, Anthony stayed home sick with a cold. Rockmore was at class when she got a call just after lunchtime from her aunt.

Anthony was at the hospital, her frantic aunt told her. The police had taken Craig into custody.

At the hospital, Anthony lay unconscious, an ugly wound on the left side of his small head. Doctors soon declared him brain-dead. Rockmore and Anthony's birth father, for whom the boy is named, agreed to keep him alive for organ donation.

Craig is being held at the Curran-Fromhold Correctional Facility on $500,000 bail, with a preliminary hearing scheduled for May 30, according to court records.

His criminal record includes at least 10 arrests, mostly for robbery, theft and related offenses.

In Anthony's case, he is charged with aggravated assault, endangering the welfare of children, possession of instruments of crime and related crimes. His charges likely will be upgraded when Anthony is taken off life support.

Alicia Taylor, a spokeswoman for the city's Department of Human Services, declined yesterday to say whether the family had any prior DHS involvement.

Yesterday, as a steady stream of friends visited Rockmore to offer hugs and condolences, the distraught mother - still wearing her plastic hospital bracelets - remembered her boy as "a Power Rangers freak" and fan of the Disney cartoon "Jake Long: American Dragon."

He liked rough-housing with his cousins, but still was so gentle that he was his preschool "class protector," Rockmore said. "If somebody was being mean to somebody else, Anthony would be there telling them to stop. He was the one who took up for everybody else."

He loved firefighters, police, ambulances, motorcycles, football, wrestling - "all that boy stuff," his mother said. "He said he wanted to be a police officer Monday through Wednesday; Thursdays through Saturdays, he wanted to be a firefighter; and on Sunday, he wanted to ride his motorcycle all day."

Sympathetic neighbors made plans to put up a teddy-bear memorial and lamented that a child could endure such monstrous mistreatment on their block without them noticing.

"It's just sad; I feel bad for her," said neighbor Renee Smith. "I have a 3-year-old granddaughter who was his classmate. When I look at her, I think about him."

Homicides of children remain rare in Philadelphia.

Of 117 slayings so far this year, just one involved a victim under the age of 6, according to police data. That's down from three homicides of tots age 5 or younger last year and nine the year before, according to the data.

In the most recent baby homicide case, police charged Jose Rivera Colon, 31, of Northeast Philadelphia, with the murder of his live-in girlfriend's 1-year-old son, Aiden J. Salber-Dowd, police Spokeswoman Officer Christine O'Brien said.

Aiden had been under "extensive medical care" since Colon allegedly assaulted him on April 12, 2007; the baby succumbed to his injuries almost a year later, on April 4, O'Brien added. *