Carter, 34, was found dead in the bathtub at his California home on Saturday.
The Los Angeles County coroner’s office performed an autopsy on Carter, but officials told the Los Angeles Times that they would defer declaring a cause of death pending chemical tests.
In a statement to Deadline, the coroner’s office said it needed additional information to determine the cause and manner of death.
Carter, the younger brother of the Backstreet Boys’ Nick Carter, had several hit songs as a teenager and performed as the opening act for the Backstreet Boys and Britney Spears, The Associated Press reported.
Carter had been open about his struggles with substance abuse, and spent time in rehab in 2017 after an arrest on suspicion of driving under the influence and marijuana charges, the AP reported.
A source familiar with the investigation told the Los Angeles Times that investigators found medications and compressed air in Carter’s master bedroom and bathroom.
1997 AARON CARTER CELEBRATES 10TH BIRTHDAY AT DISNEYLAND PARIS (Jeremy Bembaron/Sygma via Getty Images)
2001 Aaron Carter performs the unreleased debut single, "A.C.'s Alien Nation", off of the Jimmy Neutron: Boy Genius soundtrack at the nick.com studios in New York City 8/7/01. His new album, "Oh Aaron" arrived in stores today, August 7. Jimmy Neutron: Boy Genius will be released in December 2001. (Scott Gries/Getty Images)
2001 Aaron Carter at KIIS-FM's 'Wango Tango' at Dodger Stadium in Los Angeles, Ca. 6/16/01. (Kevin Winter/Getty Images)
2001 Aaron Carter performs at the Teen Choice Awards 2001 held at the Universal Amphitheatre in Los Angeles, CA., August 12, 2001. (Kevin Winter/Getty Images)
2002 Aaron and Nick Carter backstage at KIIS-FM's All-American Wango Tango at the Rose Bowl in Pasadena, Ca. Saturday, June 15, 2002. (Kevin Winter/Getty Images)
2003 HOLLYWOOD, CA - APRIL 26: Actress Hilary Duff (L) hugs singer Aaron Carter as they attend the premiere of The Lizzie McGuire Movie on April 26, 2003 in Hollywood, California. (Lucy Nicholson/Getty Images)
2004 HOLLYWOOD, CA - APRIL 14: Aaron and Nick Carter (L) aririve for the "Simple Life 2" Welcome Home Party at The Spider Club on April 14, 2004 in Hollywood, California. (Frazer Harrison/Getty Images)
2005 NEW YORK - JUNE 29: Singer Aaron Carter signs an autograph during an interview at Dewey's Flatiron June 29, 2005 in New York City. (Scott Gries/Getty Images)
2006 LOS ANGELES, CA - JULY 11: Singers Aaron Carter (L) and Nick Carter (R) attend the Celebrity Locker Room "An All Star Night At The Manion" at the Playboy Mansion on July 11, 2006 in Los Angeles, California. (Michael Buckner/Getty Images)
2007 LOS ANGELES, CA - MARCH 31: Singer Aaron Carter (L) and rap artist Romeo pose in the Distinctive Assets gift lounge during the 20th annual Kid's Choice Awards at Pauley Pavilion on March 31, 2007 in Los Angeles, California. (Michael Buckner/Getty Images)
2007 LOS ANGELES, CA - MARCH 31: Singer Aaron Carter is interviewed in the Distinctive Assets gift lounge during the 20th annual Kid's Choice Awards at Pauley Pavilion on March 31, 2007 in Los Angeles, California. (Amanda Edwards/Getty Images)
2009 SANTA MONICA, CA - NOVEMBER 22: Dancers Aaron Carter (L) and Karina Smirnoff (R) attend the 11th Annual Day of The Child Event on November 22, 2009 in Santa Monica, California. (Valerie Macon/Getty Images)
2012 NEW YORK, NY - JANUARY 19: Singer Aaron Carter performs at the Gramercy Theatre on January 19, 2012 in New York City. (Cindy Ord/Getty Images)
2014 HOLLYWOOD, CA - AUGUST 21: Singer Aaron Carter attends Dave & Buster's Hollywood & Highland Grand Opening on August 21, 2014 in Hollywood, California. (Mark Davis)
2016 LOS ANGELES, CA - FEBRUARY 14: Singer Aaron Carter attends the GBK Pre Grammy Lounge at Tom's Urban at L.A. Live on February 14, 2016 in Los Angeles, California. (Jerod Harris)
2017 CARSON, CA - MAY 13: Madison Parker (L) and Aaron Carter attend 102.7 KIIS FM's 2017 Wango Tango at StubHub Center on May 13, 2017 in Carson, California. (Frazer Harrison/Getty Images)
2019 WEST HOLLYWOOD, CALIFORNIA - OCTOBER 10: Jane Carter and Aaron Carter attend WE tv Celebrates the 100th Episode of the "Marriage Boot Camp" reality stars franchise and the premiere of "Marriage Boot Camp Family Edition" at SkyBar at the Mondrian Los Angeles on October 10, 2019 in West Hollywood, California. (Randy Shropshire/Getty Images for WE tv)
2021 PHILADELPHIA, PENNSYLVANIA - APRIL 10: Aaron Carter (R) and his fiancée Melanie Martin attend the Celebrity Boxing Face Off between Lamar Odom & Aaron Carter on April 10, 2021 in Philadelphia, Pennsylvania. (Gilbert Carrasquillo/WireImage)
2021 PHILADELPHIA, PENNSYLVANIA - APRIL 10: (L-R) Lamar Odom, Celebrity Boxing Founder Damon Feldman and Aaron Carter attend the Celebrity Boxing Face Off between Lamar Odom & Aaron Carter on April 10, 2021 in Philadelphia, Pennsylvania. (Gilbert Carrasquillo/WireImage)
2022 LAS VEGAS, NEVADA - FEBRUARY 12: Singer and producer Aaron Carter arrives at the "Kings of Hustler" male revue at Larry Flynt's Hustler Club on February 12, 2022 in Las Vegas, Nevada. (Gabe Ginsberg/Getty Images)