COLUMBUS -- A federal court on Jan. 26 blocked three executions scheduled through April, determining the new lethal injection process adopted by the state was unconstitutional.

U.S. Magistrate Judge Michael R. Merz barred the state from executing Ronald Phillips, Raymond Tibbetts and Gary Otte using the three-drug protocol it announced late last year or "any lethal injection method which employs either a paralytic agent or potassium chloride."

Phillips, convicted in the brutal rape and murder of an Akron girl in 1993, was scheduled to be executed on Feb. 15.

Otte, who killed two people in Cuyahoga County in 1992, had a March 15 execution date.

And Tibbetts, who murdered his wife and an elderly man in 1997, was scheduled for execution on April 12.

The ruling is the latest in a years-long legal challenge over Ohio's lethal injection protocols, following the execution of Dennis McGuire in January 2014.

McGuire, who received a capital sentence for the rape and murder of a pregnant Preble County woman, gasped for breath during what witnesses described as a prolonged procedure under the state's two-drug execution method.

In early 2015, state prison officials abandoned that combination, switching to two different drugs, though that protocol has not been used.

The state and others have struggled to find supplies of execution drugs, after manufacturers blocked their use for lethal injections. State law changes enabled the purchase of drugs from compounding pharmacies, under legislation that allowed the names of those businesses to be kept secret, but prison officials have not identified or obtained supplies in that way.

In October, state prison officials announced a new three-drug lethal injection protocol, using midazolam, rocuronium bromide and potassium chloride.

But legal counsel for Phillips, Tibbetts and Otte challenged the constitutionality of the proposed three-drug lethal injection, arguing that the state's new protocol amounted to a "reversion to a 'more primitive, less humane execution method'" and created "a substantial risk of serious harm," according to documents.

Merz agreed, noting in the Jan. 26 ruling, "The court concludes that use of midazolam as the first drug in Ohio's present three-drug protocol will create a 'substantial risk of serious harm' or an 'objectively intolerable risk of harm'"

More than 30 executions are scheduled through early 2021.

Marc Kovac is the Dix Capital Bureau Chief. Email him at mkovac@dixcom.com or on Twitter at OhioCapitalBlog.