Federal investigators have released a wanted poster for 23-year-old Justin Smith.
Click to enlarge FBI Wanted Poster
According to the FBI, Smith has connections to New Castle, Delaware; Greensboro, North Carolina; the Little Haiti neighborhood of Miami, Florida; and Atlanta, Georgia.
A reward is being offered for information leading directly to the arrest of Smith, the FBI said.
Brice was found dead on the 5800 block of Eastwick Avenue in Southwest Philadelphia on April 5.
Police said the Delaware County mother was shot multiple times in the head.
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Investigators believe Smith fatally shot Brice inside his car.
That car was found engulfed in flames in the area of 59th and Florence streets in Philadelphia just hours after Brice and Smith were seen at K Laundry in Yeadon on March 30.
No one was found inside the vehicle. The car was discovered about a mile from where police said Brice's body was discovered in the woods days later.
Woman arrested in connection with death of pregnant mother Dianna Brice
Last week, Philadelphia police announced the arrest of 21-year-old Tylydia Garnett in connection with Brice's death. She was charged with arson, abuse of a corpse and related offenses.
Investigators said Garnett was seen on video buying gasoline before returning to a garage that was either rented or owned by Smith.
They loaded a something into Garnett's car, which is believed to be Brice's body.
Investigators said Garnett then followed Smith to the location on Eastwick Avenue where Brice's body was found.
The Philadelphia District Attorney's Office said Garnett fled to Florida after helping to dispose of Brice's body. She was released after posting 10% of $75,000 bail.
WATCH: Philadelphia DA's Office provides update on Dianna Brice murder case
Philadelphia DA's Office provides update on Dianna Brice murder case
Brice's mother, Betty Cellini, said her daughter had a young son and was 14 weeks pregnant. She also had a life-threatening medical condition that required medication.
Before Brice vanished, Cellini said her daughter and Smith were involved in an argument.
On April 9, Smith was charged with murder and related offenses.
The FBI said Smith should be considered armed and dangerous.
Anyone with information is asked to contact the local FBI office.