The Washington Post calls it “state-sponsored killing spree,” with Arkansans have now executed three of the eight men it's seeking to put to death this month. On Monday, 52-year-old Jack H. Jones was injected with a controversial three-drug cocktail that left him catching his breath — and, some witnesses say, in pain — before being declared dead at 7:20 pm.

Jones' execution was one of two people executed on Monday, the other being Marcell Williams. It was the first one-day double execution to be performed in nearly two decades. Another man, Ledell Lee, was executed on April 20, the same day the Supreme Court allowed Arkansas to continue using a potentially ineffective sedative, midazolam, to put prisoners to death. The state had faced judicial setbacks over its plans to use the drug as part of its lethal cocktail — and has been rushing to use it this month before it expires.

Questions have been raised about the humaneness of Arkansas moving forward with the five other executions in light of claims its drug cocktail is not quick and painless. Associated Press reporter Andrew DeMillo said he they did not see pain on Jones’ face as he died, but others have said that Jones’ gasps for air could be a sign that he was suffering as he died.

Arkansas and other death-penalty states have struggled to obtain reliable drugs for use in executions since many pharmaceutical companies have refused to sell their products to them, responding to campaigns launched by activists opposed to the death penalty. As a result, states have turned to untested methods, with Arizona and Ohio both carrying out executions that resulted in dying inmates gasping for breath, sometimes for hours.

In Alabama, Ronald B. Smith was injected with a three drugs and proceeded to struggle to breath, heaving and coughing on the execution table for 13 minute while onlookers made no attempt to stop the procedure, according to those present.

Kenneth Williams is expected to be executed in Arkansas on Thursday, according to The Marshall Project.