By her own admission, Grace Trotman helped her former boyfriend hide his 2-year-old son’s body in a concrete coffin after the toddler’s death two years ago. But her testimony also helped send that man to prison.

Those will be the factors at play today when Circuit Judge Markley Dennis sentences the 27-year-old Summerville woman in connection with the 2010 death of Rodricus Williams. Trotman pleaded guilty in February to homicide by child abuse and desecration of human remains.

Trotman made a plea deal with prosecutors that also set the parameters for her sentencing, which is expected to place her behind bars for two decades.

Part of the plea called for Trotman to cooperate with prosecutors and testify against her ex-boyfriend, 31-year-old Roger Williams, in his October trial for the death of his son. The trial ended with a conviction for Williams and a life prison term on charges of homicide by child abuse and unlawful conduct toward a child.

Shaneka Washington, Rodricus’ mother, knows how important Trotman’s testimony was in convicting Williams.

“She played a good part in the trial,” Washington said.

Washington intends to be present for Trotman’s sentencing today in Circuit Court in downtown Charleston before Dennis, who sentenced Williams in Moncks Corner.

In return for her guilty plea, prosecutors agreed to drop a charge of unlawful conduct toward a child. The agreement also calls for her to receive a 20-year sentence on each remaining charge, but those terms would be served concurrently.

She fulfilled her part of the deal during Williams’ trial, where she described to a jury how he treated his own son.

“He didn’t want him to be his son,” Trotman testified.

Trotman said she “popped” the toddler shortly before he died, causing him to hit his head on a wall, but the prosecution contends it was Williams’ continuous beating of the toddler and neglect that led to his death on June 6, 2010.

Williams then stuffed his son’s lifeless body into a trash can and filled it with cement, according to prosecutors. He and Trotman left the encased remains behind a trailer near Orangeburg.

The pair concocted a story about the boy, pretending to lose the child at The Battery in downtown Charleston about a month after the child’s death.

After lying to police and a massive search for the child, Trotman ended up telling investigators where the boy’s body was and led them to it.

Reach Natalie Caula at 937-5594 or Twitter.com/ncaula.