Casey Johnson was laid to rest at her family's estate in New Brunswick, New Jersey on Tuesday, UsMagazine.com has learned.

"Today was just a private, open casket funeral for immediate family," a source tells Us, adding that a memorial for close friends is set to take place in the next several days.

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Missing from Tuesday's service: Johnson's purported fiancee, reality star Tila Tequila, who has engaged in a war of words with Johnson's pals who claim Tila was using Johnson for media attention.

"She wants so badly to go to the funeral, but nobody will give her the details or tell her anything," a source told Us. "She is extremely frustrated, as what she shared with Casey was real and special. Nobody understood."

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Johnson, who suffered from diabetes, was found dead at age 30 at her L.A. home Jan. 4. A cause of death has yet to be determined.