New York (CNN) -- A grand jury indicted Levi Aron on Wednesday as authorities revealed new details about the death of the 8-year-old Brooklyn boy he is accused of kidnapping and killing last week.
The grand jury indicted Aron, 35, on eight counts, including two of felony murder in the first degree. If convicted, he would face a maximum sentence of life in prison without parole, Kings County District Attorney Charles Hynes announced.
Hynes had said he would ask a grand jury for the "maximum charges permitted by law" for "the vicious and callous murder and dismemberment of 8-year-old Leiby Kletzky."
The indictment accuses Aron of abducting Kletzky in his Brooklyn neighborhood on July 11. After kidnapping the boy, the indictment says, Aron took him to Aron's apartment and killed him there, according to a statement from Hynes' office.
"I should note that the child's body contained marks on the wrist ... which would indicate at some point that he was tied," Hynes told reporters.
Hours before Hynes announced the indictment, New York City's chief medical examiner said that Kletzky died after being drugged and then smothered.
"We charge that the child was kept for more than 12 hours, that it was an intent to kill, and that's based on ingestion of the medication," Hynes said.
The autopsy results for Kletzky listed a cocktail of four prescription and over-the-counter drugs in the boy's system: cyclobenzaprine, a muscle relaxant; quetiapine, an antipsychotic drug; hydrocodone, a pain medication; and acetaminophen, the drug found in Tylenol, according to a statement from the medical examiner's office.
Kletzky disappeared July 11 while walking home alone from his summer day camp. Police located human remains in Aron's freezer during a search of the Brooklyn neighborhood, as well as in a trash bin. Both Aron and Kletzky are members of the borough's close-knit Orthodox Jewish community, although police say it doesn't appear that they knew each other.
On Wednesday, Hynes detailed some of the evidence that he alleged links Aron to the kidnapping and killing -- including extensive video footage that shows Kletzky talking to a man and following him to a brown car authorities later traced to Aron. Detectives later concluded that Aron was also the man they saw in the video footage, Hynes said.
Aron, who was being held without bail, did not enter a plea at his arraignment last week. He is under a suicide watch. A mental evaluation that his attorneys asked be conducted on their client has been completed but the results have not been released, said attorney Gerard Marrone.
New York Police Commissioner Ray Kelly said last week that Aron told authorities he was sorry for the trouble he has caused. Statements made by the suspect indicated that he kidnapped Kletzky and, as the neighborhood search for the boy intensified, he panicked and killed him, Kelly said.
Aron is currently at Bellevue Hospital Center, where doctors are examining him, Hynes said.
"His mental capacity is a question for the doctors," Hynes said, adding that he expected their findings to be released before a scheduled court appearance July 28.
Defense attorneys Marrone and Pierre Bazile say Aron has said he hears voices and hallucinates.
"He's been hearing voices for quite some time," Marrone told reporters at a news conference Monday, adding that his client tries to silence the voices by listening to music. "He listens to it with earphones and he listens to it very loud, and that helps him quell some of his voices."
"I have sincerest concerns about the defendant's mental state and his cognitive abilities," Bazile said Wednesday.
Kelly called the case "heartbreaking."
"Obviously in this business you see a lot of violence, but there's usually some sort of irrational twisted logic that's given to why a violent event took place," Kelly said in a news conference last week.
"Here, I mean, it's just, it defies all logic and I think that's what's really so, so terribly disturbing about this case. There's absolutely no reason. There's nothing more innocent than an 8-year-old child and to be, you know, killed in this manner it's just ... heartbreaking."
On the day he disappeared, Kletzky was supposed to meet his parents after walking seven blocks from his summer day camp, but he became lost and asked the suspect for directions, Kelly said.
Surveillance video showed Aron entering a dentist's office while Kletzky waited for him across the street for seven minutes, Kelly said.
Aron claims he took Kletzky to a wedding July 11 in Monsey, New York, and then brought him back, Kelly said. Police said Aron went to the wedding, but they have not been able to confirm that Kletzky went with him, as no one has said they saw him.
Hynes said Wednesday that authorities have evidence showing that Kletzky had been in Monsey, saying a clerk reported seeing the boy at a gas station there.
According to Kelly, police showed up at Aron's third-floor attic apartment at 2:40 a.m. July 13 and asked him about Kletzky's whereabouts. The suspect pointed them to the kitchen, where blood was visible on the freezer handle. Inside the refrigerator was a cutting board with three blood-spattered carving knives, Kelly said.
Remains were found in Aron's freezer and in a trash bin more than two miles away, wrapped in a black plastic garbage bag inside a suitcase, Kelly said.
Aron worked as a clerk at a maintenance supply company, authorities said. His only known criminal summons was for urinating in public last year.
The grand jury's charges against Aron on Wednesday also included three counts of murder in the second degree, two counts of kidnapping in the first degree and one count of kidnapping in the second degree.
CNN's Jesse Solomon, Nina Raja and Leigh Remizowski contributed to this report.