Alvarez told investigators that after receiving a distress call from another worker June 25, he rushed up the stairs of Jackson's home and entered a bedroom to find the singer lying on a bed with his arms outstretched and his eyes and mouth open.
The King of Pop had an IV attached to his leg and was laying there lifeless. At his side, Jackson's personal physician, Dr. Conrad Murray, was performing mouth-to-mouth resuscitation while Alvarez took over CPR.
When Alvarez asked what happened to the singer, Murray replied, "He had a reaction, he had a bad reaction."
Alvarez told investigators that Murray grabbed the drug vials and told him to put them in a bag. He says that Murray waited until the bags were filled before telling Alvarez to call 911.
Alvarez's report could be a strong blow to Murray's defense, according to ABC News legal expert Dana Cole.
"If these allegations are true, then they could demonstrate what we call a 'consciousness of guilt,'" said Cole. "Instead of attending to the patient he is basically tampering with a crime scene. That is never good."
Dr. Murray's defense team rejects the accusation that Murray was covering up anything and says Alvarez's accounts simply don't add up.
Murray's lawyer, Ed Chernoff, says that Alvarez was interviewed twice by police and gave different accounts of what happened in Jackson's bedroom. During the first interview, he made no mention of being told to tidy away medicine vials.
"He didn't say any of those things, then two months later, all of a sudden, the doc is throwing bottles into the bag," Chernoff said. "Alvarez's statement is inconsistent with his previous statement. We will deal with that at trial."
"If it is only now that this is coming out that this is what he recalls, then to me that might be considered an inconsistency in what he told police earlier," said Cole. "Therefore it may not be as damaging to the doctor."
Attorney Brian Oxman, who represents the Jackson family, has a different perspective.
"That is the consciousness of guilt," said Oxman. "The bottom line here is it's not just involuntary manslaughter this is murder in the second degree."
Murray has been charged with involuntary manslaughter for administering drugs to Jackson at home -- including a hospital grade anesthesia -- without proper resuscitation equipment on hand.
"There were nine different drugs in Michael Jackson's system," said Oxman. "This man represented himself. He told more falsehoods, more stories, and changed his story more times than a snake changes his skin."
Two of the star's children, Prince and Paris, came in the room and cried as they saw Murray trying to save their father. They were quickly ushered away.
The documents also detail an odd encounter with Murray after Jackson was declared dead at UCLA Medical Center.
Murray insisted he needed to return to the mansion to get cream that Jackson had "so the world wouldn't find out about it," according to the statements, which provide no elaboration.
A coroner's report found that Jackson died from an overdose of the powerful anesthetic propofol and two other sedatives administered by Murray. The singer was 50 years old.
Murray, a Caribbean born physician who had been hired by the superstar to look after his health during a rigorous comeback tour, told police he gave Jackson propofol and other sedatives to help him sleep.
Murray will be back in court for a hearing April 5.
The Associated Press contributed to this report.