MEXICO CITY  The story is as convoluted as a film noir plot. A prominent lawyer is murdered after he accuses the president of plotting to kill him. But an international investigation finds that the murder was actually planned by the victim himself and carried out in a way that appeared intended to inflict maximum damage on the government.

Bizarre as the story is, its conclusion is likely to put an end to a political crisis in Guatemala that has threatened the survival of President Álvaro Colom’s government.

Vindicated by the results of the United Nations-sponsored report that has cleared his name, Mr. Colom on Wednesday declared victory over political opponents who had called for his resignation. “This strengthens both my government and my country,” Mr. Colom said in a telephone interview.

The lawyer in question, Rodrigo Rosenberg, was shot five times on May 10 while riding his bicycle. A day later, a videotape that he made earlier surfaced. He said, “Unfortunately, if you are watching the message, it is because I was assassinated by President Álvaro Colom.”