A Sherwood couple say they came home from a date night a couple of months ago to find their 1-year-old son, Jacob, screaming and the babysitter asleep on the couch. The next morning, they awoke to find him covered in bruises.

The parents say they believed they had a solid case so went to police. Weeks went by. No criminal charges were filed.

The boy's father, Joshua Marbury, took to Facebook on Friday to express his outrage over an Oregon court ruling that he says prevented his son's alleged abuser from facing charges. The post soon went viral, reaching more than 100,000 shares within a day.

Doctors noted that Jacob's bruising showed a handprint, Marbury wrote, and a detective told the parents the abuse could have killed the baby.

"Something needs to be done," Marbury wrote. "NOBODY can just hit a child and more to just get away with it because the child (can't) verbally tell you."

I normally keep my matters with family very private cause i dont need the attention. But this is different. TWO months... Posted by Joshua Marbury on Friday, May 20, 2016

Marbury was referencing a 2012 Oregon Court of Appeals ruling that prosecutors say made it more difficult to file charges in abuse cases with victims who can't speak.

Alicia Quinney, Jacob's mother, said she consoled her son when she returned home that night in March. But she was shocked by what she saw the next morning.

"The first thing I saw was a black eye," she said. "I thought maybe marker got on his face or something. When he turned over, his whole right side of his face -- black and blue."

There were more marks on the boy's right ear, arm and back, she said.

Quinney said she believed the babysitter had hurt her son. She took Jacob to the hospital, she said, where Sherwood police responded and began investigating.

The parents said they learned Friday the case would not be prosecuted, in spite of photos that show Jacob severely bruised.

Washington County Deputy District Attorney Dustin Staten emailed Quinney a link to a story published by The Oregonian/OregonLive detailing the challenges the law poses for prosecutors. The headline: "Even pets are better protected than young kids under Oregon abuse laws, prosecutors say."

To convict a suspected child abuser of felony assault or criminal mistreatment, the article explained, prosecutors must prove that the victim suffered a "physical injury" under Oregon law. That means proving the child experienced "substantial pain."

But appellate rulings have made that hard to prove if victims can't talk about the extent of their suffering. Prosecutors say children younger than 5 often aren't able to articulate "substantial pain." The same can be true for older children with developmental disabilities or those who don't want to speak out against their abusers.

The law leaves open another avenue for proving a "physical injury" - that the victim suffered an "impairment of a physical condition." But the Oregon Court of Appeals has ruled that welts, bruises and shallow cuts aren't enough.

Jacob's bruises faded, but his mother says she noticed a lasting change in him after the incident.

"He's always been a mama's boy, very much," she said. "But since this happened he's been a mama's boy times 100."

The parents, too, have suffered, Quinney said. She said she doesn't feel comfortable leaving him with other people.

"My trust with so many people is shot," she said. "This isn't something we can move on from."

Quinney said she wants the law to better protect victims. And she wants the person she says hurt Jacob to be held accountable. After Marbury's Facebook post, there may be a greater chance for that.

Staten, the prosecutor, said he hadn't previously seen the photos Jacob's father posted to Facebook.

"Seeing those photos has caused me to want to take a different path," Staten said Saturday in a phone interview with The Oregonian/OregonLive.

There were investigative photos taken in Jacob's case, Staten said, but "there's additional people I need to consult with based on those photos I've seen today."

The Oregonian's Aimee Green contributed to this report.

-- Emily E. Smith

esmith@oregonian.com

503-294-4032; @emilyesmith