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CLAYTON, Mo. (AP/KMOV) -- Court proceedings continued Tuesday in the first-degree murder trial of Kevin Johnson, who confessed to killing Kirkwood Police Sergeant William McEntee.

On Tuesday, Kevin Johnson's cousin, Jermaine Johnson took the stand and testified against his cousin, telling the court what he saw on the day Sergeant McEntee was shot.

Jermaine Johnson said that he saw Kevin shoot Sergeant McEntee, and then saw McEntee's head jerk back and blood pouring from his head.

The prosecutor asked Jermaine if it made him sick and he said that it did. Jermaine said that Kevin called him a name for throwing up at the sight.

When asked why he cooperated with police, Jermaine said that the incident was messing with him.

St. Louis County prosecutor Robert McCulloch is seeking the death penalty for the 22-year-old Johnson.

The trial is his second. The first, in April, ended with a deadlocked jury.

McEntee was killed on July fifth, 2005.

The defense says that Johnson will take the stand again.

This time he will claim like he did the first time that he shot McEntee without thinking. Johnson said that he was so distraught over the death of his little brother earlier that day that he was not thinking clearly when he shot McEntee.

There have already been several witnesses taking the stand.

A divided jury earlier this year could not decide on first or second-degree murder, so a judge declared a mistrial, and now prosecutors will get a second chance.

Prosecutors say Johnson not only did it, but when he saw McEntee still moving, he walked up to him and shot him execution style in the back of the head.

If Johnson changes his story even a little, prosecutors can play video of his testimony from the first trial in hopes of making him look like a liar.

Johnson's defense lawyers said that won't happen because he has no intention of changing his story. 

With a first-degree murder conviction Johnson could get the death penalty or life without parole.

Under a second-degree murder conviction he could one day be paroled.