Hernandez’s arraignment came on the same day that the Cleveland Browns rookie linebacker Ausar Walcott was charged with attempted murder after he reportedly punched a man in Passaic, N.J. The Browns released Walcott on Wednesday.

The killing of Lloyd, according to the prosecutor William McCauley, was a protracted drama, and it included Lloyd’s apparently growing nervous about Hernandez’s intentions as he sat in a car with him. In his final moments alive, Lloyd texted his sister to alert her. When she asked whom he was with, he answered, “NFL,” and added, “Just so you know.”

The murder on June 17, the prosecutors said, was gruesome. Lloyd, a semipro football player, was shot multiple times, with the two final shots fired by someone standing directly above him. Hernandez, the prosecutors said, felt betrayed; Lloyd, who had been dating his fiancée’s sister, had talked to some people Hernandez “had troubles with” when the men were out together on June 14.

The motive for the killing might have been age-old, but the police used a variety of modern investigative methods and relied on the technology of connected and interactive devices to build their case against Hernandez. Piecing together cellphone tower tracking, text messages and surveillance tapes — including video recorded by 14 cameras trained on the outside and inside of Hernandez’s home — the police constructed a timeline and concluded, in the words of McCauley, that Hernandez “orchestrated the execution” of Lloyd, 27.

Prosecutors said that home surveillance videos from Hernandez’s house showed him in possession of firearms before and after Lloyd was killed; that Hernandez was observed picking up Lloyd at 2:30 a.m. on the night he was killed; that a silver Nissan Altima — the same make of vehicle Hernandez had rented — was seen going to and coming from the site where Lloyd’s body was found; and that Hernandez was seen leaving his vehicle with a gun at his home at 3:29 a.m., shortly after the authorities say Lloyd had been murdered.