On July 11th, the FBI involved themselves in the case after the 7 day waiting period. The only evidence the FBI had to work with, at this time, was the ransom note. Handwriting experts taught the FBI how to analyze handwriting. On August 22nd, 1956. after analyzing two million samples, the search ended. Agents noticed a similarity between the handwriting in the ransom note and handwriting in a probation file, which led to a suspect named Angelo LaMarca. LaMarca was arrested on August 23rd, 1956. He denied involvement in the case but soon confessed after seeing the handwriting comparisons. LaMarca told police he abandoned Peter alive in a heavy "brush" off an highway exit. After search of the area, the decomposed remains of Peter's body were found. LaMarca was charged for kidnapping and murder, and was sentenced to death on August 7th, 1958.