Originally Published: 01 FEB 23 14:48 ET

By Delaney Tarpley

COLUMBIA, Missouri (KOMU) -- Leonard "Raheem" Taylor is set to be executed next Tuesday. He was convicted of the quadruple murder of his girlfriend and her three young children.

Back in December of 2004, Taylor's girlfriend, Angela Rowe, and her three children were found shot to death in their St. Louis area home.

Advocates at a presentation on Tuesday, though, say new evidence is showing there's too much doubt to go forward with the execution.

"We are concerned there's a strong possibility he was wrongly convicted," Jeff Stack, coordinator of the Mid Missouri Fellowship of Reconciliation said.

Stack said Taylor was unable to afford his own attorney during the case.

Throughout the trial, Taylor maintained his innocence, saying he was in California at the time the murders could have taken place.

Recently, his daughter confirmed his testimony, saying he was in California at the time visiting her. She, her sister, and her mother submitted affidavits with the same information.

The prosecutor's case relied heavily on a police interview with Taylor's brother, Perry Taylor. Perry told police during a three hour interrogation that his brother had killed Rowe and her children before flying to California on November 26, 2004. He later recanted his statement during the trial, saying he was threatened and coerced into making that statement.

Several witnesses, including a neighbor, Rowe's sister, and two aunts of the children also reported speaking to Rowe in the week following November 26, while Taylor was reportedly in California.

"There are way too many questions in this particular case for anyone to be comfortable carrying out an execution," Michelle Smith, co-director of Missourians to Abolish the Death Penalty said. "I don't believe we should have them period, but for these people who do, we should definitely draw a line at questions about innocence and making sure the person is actually guilty."

Taylor has maintained his innocence the past 15 years he's been in prison. If the execution goes forward, he will be the third person the state of Missouri has executed in the past 10 weeks.