(NewsNation) — The execution of Michael Dewayne Smith was “heartbreaking” and lacked humanity, according to the Rev. Jeff Hood, Smith’s spiritual adviser.

Thursday morning, Smith received a lethal injection at the Oklahoma State Penitentiary in McAlester and was pronounced dead at 10:20 a.m., Oklahoma Department of Corrections spokesperson Lance West said.

Hood went into the chamber with Smith and said the execution was slower than expected. As the execution proceeded, Hood said he expected Smith to make a final last statement, but he remained silent.

“For everyone there, it’s painful. It’s unnerving. … I looked at Michael, I could tell he was close to death. The last thing I saw was a little tear on his cheek. … I’m aware a lot of people don’t have sympathy for him. But it’s not something we have to do,” Hood said on “Banfield.” “We don’t have to kill each other in order to teach each other not to kill each other.”

Smith was convicted of two murders in Oklahoma City. The first victim, 40-year-old Janet Moore, was shot at her apartment. The second victim, 24-year-old Sharath Pulluru, was shot nine times at a convenience store, then doused with lighter fluid and set on fire.

Prosecutors said the evidence against Smith is overwhelming.

He became the fourth inmate in the nation this year to be put to death, the Oklahoman reported.

A total of 27 states in the U.S. have the death penalty.  Oklahoma, Texas and Missouri are responsible for the most prison executions per capita since 1976, according to the nonprofit Death Penalty Information Center

Five states — Alabama, Florida, Missouri, Oklahoma and Texas — carried out executions last year.

The public’s opinion is shifting, too. Half of Americans say the death penalty is administered unfairly, according to the findings of a November Gallup poll. That’s compared to 47% who said the practices are fair. Still, a plurality of voters say the death penalty isn’t used enough.