Batchelor made his first court appearance at the jail in Sharpes Wednesday afternoon where a judge ordered he be held on no bond.
"He's not entitled to bond under these circumstances," prosecutor Gary Beatty said to a judge.
WFTV first reported when Marks' body was found inside his burned out car last January. Police still don't know how he died, because his body was so badly burned.
Investigators say they have witnesses that say Batchelor was the last person to see Marks alive, and police say Batchelor asked people to lie for him to create an alibi. Now that he's behind bars, officers say they are getting even more evidence that Batchelor is the killer.
Noting the death penalty was a possible punishment, prosecutors asked the judge to keep 21-year-old Keith Batchelor in custody until his trial. The Palm Bay bouncer is accused of killing 18-year-old Isaiah Marks and setting his car on fire to destroy the evidence.
Investigators believe Batchelor was upset Marks was moving in with his ex-girlfriend and taking care of their newborn daughter.
"He was going to great extent trying to break them up and nothing was working," said Detective Ernie Diebel, Palm Bay Police Department.
Marks told his mother there was trouble. She suspected Batchelor from the beginning.
"He said, 'It's alright momma, I can handle him. It's no problem. It's alright,'" Marks' mother, Mary Pollard, said.
Police say, before the murder, Marks believed Batchelor slashed his tires and poured sugar in his gas tank.
Investigators admit they don't have any physical evidence tying Batchelor to the burned up car, but they say they found witnesses who saw Batchelor with Marks just before he died. They also have cell phone records showing Batchelor was in the area where the car was burning.
Batchelor, the son of a convicted killer, has denied having anything to do with the death, but police say they have caught him in a web of lies.
Police say, even after Marks was killed, Batchelor went to extremes to try to get his ex-girlfriend back, repeatedly harassing her at work and even stopping her in traffic.
"This is after the killing, he kept on trying to get back with her and wouldn't take no for an answer. She finally couldn't take anymore and left," said Detective Ernie Diebel.
She moved out of the area and the judge forbade him from contacting her.