Prosecutors have charged a 36-year-old Sunnyside man with first-degree assault in connection with the July 11 stabbing of a woman authorities identified as his girlfriend.

In court documents filed Tuesday, prosecutors indicated that they are also seeking a deadly weapon enhancement against Tranquilino Jose Cantu-Mercado, which could add at least two years to a prison sentence if he is convicted.

Yakima police were called to Astria Regional Medical Center around 5:20 p.m. July 11 after a woman came into the hospital with stab wounds to her chest and arm, according to court documents. At that time, she claimed that she had fallen on knives while in Toppenish, but officers said her wounds were not consistent with that story, the documents said.

Later that evening, Cantu-Mercado was spotted walking in traffic and was arrested on an outstanding warrant out of Colorado, according to a probable-cause affidavit. Yakima officers found the woman’s phone on Cantu-Mercado when he was arrested, the document said.

Officers again questioned the woman, who told them that Cantu-Mercado stabbed her repeatedly, the documents said, while sitting in a car near Granger. Cantu-Mercado, she said, accused her of trying to get his brother killed before he stabbed her, the documents said.

The investigation has been turned over to the Yakima County Sheriff’s Office because of where the crime was said to have happened.

At a preliminary hearing Friday, Yakima County Superior Court Judge David Elofson set Cantu-Mercado’s bail at $100,000 for the assault and added an additional $100,000 for the Colorado warrant.

Cantu-Mercado is scheduled to be arraigned on July 26.

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He has been ordered not to contact the woman.

Reach Donald W. Meyers at dmeyers@yakimaherald.com or on Twitter: donaldwmeyers,