In this April 8, 2018 photo, Puning Luk, center, the mother of slain Alejandro Villamayor, seen on the banner, attends a candle light vigil to demand justice for her son's murder in Asuncion, Paraguay. Rene Hofstetter was sentenced on Tuesday, April 10, 2018 to 12 years in prison for the murder of Villamayor, who found dead at a friend's house in June 2015 with a gunshot to the head. (AP Photo/Jorge Saenz)

ASUNCION, Paraguay - A Paraguayan court has sentenced a man to 12 years in prison for the 2015 murder of a teenage U.S. citizen, whose death originally was ruled a suicide.

In a case closely followed by the U.S. government, Rene Hofstetter, 21, was sentenced late Tuesday in the killing of his friend Alejandro Villamayor, a 16-year-old native of Rockville, Maryland, who moved to Paraguay at age 6.

Villamayor was found dead June 27, 2015, with a bullet in his temple during a trip with friends to a ranch about 250 miles (400 kilometres) south of the capital, Asuncion.

Hofstetter's fingerprints were found on the murder weapon and his father owned the ranch where Villamayor was killed. A separate court sentenced ranch worker Mathias Wilbs to two years and 10 months in jail for his role in covering up the crime to make it look like a suicide.

"We've followed the case of the youngster Alex Villamayor," U.S. Ambassador Lee McClenny said on his Twitter account. "And it's gratifying that after a long period, the case has reached closure that in some way can comfort and strengthen the Villamayor family."

His family and friends remember "Alex," as he was known to his loved ones, as a happy teen who enjoyed training at a local gym and excelled at school.

The U.S. government had expressed its concern over the initial investigation's lack of results and the case became a test of Paraguay's endemically corrupt justice system.

Villamayor's body was found with a gun in its hand and defence lawyers and prosecutors at first said his death was a suicide. But Villamayor's family always believed it was murder.

Paraguay's public ministry was forced to reclassify the case as a homicide and change the investigating team after forensic tests contradicted the prosecutors' initial suicide conclusion.

Investigators found Villamayor was holding the gun in his left hand although he was right-handed, and the weapon was not the same one that fired the bullet that killed him.

Wilbs, the ranch worker, later confessed to helping cover up the crime and placing the weapon in the teenager's hand on the orders of Hofstetter's father.

In addition, blood stains on the body indicated Villamayor's body had been turned around, and he had been dressed in clothes that did not belong to him.

A medical examiner discovered injuries on his body. Three forensic doctors said during the trial that he had suffered these injuries just a few minutes before his death.

Hofstetter travelled to Germany and only returned to Paraguay when the newly appointed prosecutors demanded an international arrest order.

News from © The Associated Press, 2018