Hexamer's sentencing hearing was adjourned Tuesday, after the Crown and defence were unable to agree on a statement of facts in the case.
Lawyers are scheduled to return to B.C. Supreme Court in two weeks, when prosecutor Elliot Poll said he will ask the court to order the psychiatric assessment.
"Ultimately, we're looking for an assessment to be done for the purposes of determining whether he is a long-term or dangerous offender," Poll told reporters outside the court.
The designations apply to violent and sexual offenders who pose a high risk of reoffending.
A judge has the option of sentencing a dangerous offender to a indeterminate sentence behind bars — meaning they can remain in jail indefinitely — or to a long-term supervision order following the completion of a specified sentence.
Long-term offenders pose risk of reoffending but have a reasonable possibility of being controlled in the community. The designation means a judge can order up to 10 years of supervision after their release from prison.
Hexamer was originally charged with 23 sex-related offences but pleaded guilty last August to three counts of sexual assault with a weapon, one count of sexual assault, and two counts of unlawful confinement involving six different victims ranging in age from six to 14.
The sex assaults started in 1995 and ended in 2009, after he sexually assaulted a six-year-old girl in Surrey, B.C.
The girl was walking with her 12-year-old brother and his 15-year-old friend, when, according to police at the time, Hexamer approached them with a knife. He threatened to stab the girl and ordered the brother and friend to follow them into the woods.
The boys were forced to lay on the ground and look away as he sexually assaulted the little girl.
Police arrested Hexamer, then 42, in December 2010, saying they had DNA evidence linking him to three crime scenes. He has been in custody since then.
The case has faced several delays as Hexamer has been represented by four different lawyers.
Poll told B.C. Supreme Court Justice James Williams that the agreement on the facts of the case with his previous lawyer "has gone by the way."
"We have not been able to agree on the facts," Poll said of the Crown and Hexamer's most recent lawyer, Donna Turko.
Turko asked for two weeks for the two parties to review the facts and try to agree. If they cannot, the Crown may call the child victims to testify, despite the guilty plea.
Hexamer, a former DJ and political campaign worker, came to court dressed in a patterned sweater, khakis and stark white prison-issue running shoes.
After a brief review of the Crown's statement of facts with his lawyer, he stared straight ahead for the duration of the brief hearing.
Hexamer worked on a municipal election campaign in Vancouver in 2005 and as a database manager in the 2006 federal election.
He had a real estate company registered in Washington state called Myriade Properties and he also operated an entertainment business called Rhythm Nation.