State of Maine v. Raymond N. Rourke III, 154 A.3d 127

In Aug. 2014 police stopped Raymond N. Rourke III for speeding, observed signs of intoxication, arrested him for OUI, and obtained an Intoxilyzer 8000 breath result of .11 g/210 L.
Rourke had told officers he was a mechanic and had been working that evening; the defense later claimed he had been exposed to automotive hydrocarbons, ketones, and toluene.
Rourke proffered expert Patrick Demers (pharmacy/forensic chemistry) to testify that inhalation of certain hydrocarbons can produce falsely elevated Intoxilyzer readings.
The State moved to exclude that testimony under M.R. Evid. 403; the court held a voir dire and excluded Demers’s opinion about interferent chemicals affecting the breath test.
The court found Demers’s supporting experiments were old, used earlier Intoxilyzer models (4011/5000), involved direct inhalation in lab settings (paint thinner), and lacked peer-reviewed support or a factual link showing Rourke’s degree of exposure.
A jury convicted Rourke; he appealed arguing the court abused its discretion by excluding the expert (and, insofar preserved, that overlapping officer testimony was cumulative). The Maine Supreme Judicial Court affirmed.

Issue	Rourke's Argument	State's Argument	Held
Admissibility of expert testimony that hydrocarbons could produce falsely elevated Intoxilyzer results	Demers should be allowed to testify that exposure to hydrocarbons/ketones/toluene could have compromised Rourke’s breath test result	Demers’s opinion is unreliable and irrelevant because his studies involved different Intoxilyzer models and lacked factual linkage to Rourke’s exposure	Court did not abuse discretion excluding the opinion: studies not factually similar, expert not familiar with Intoxilyzer 8000, and insufficient proof of Rourke’s exposure
Sixth Amendment compulsory process claim for exclusion of defense expert	Excluding Demers infringed Rourke’s right to present a defense	Exclusion was an evidentiary ruling within discretion; compulsory process not violated under facts	Court held exclusion under Maine Rules of Evidence did not violate compulsory process right

State v. Fay, 130 A.3d 364 (ME 2015) (standard for viewing evidence in light most favorable to the State)
State v. Diana, 89 A.3d 132 (Me. 2014) (abuse-of-discretion review for expert-admissibility rulings)
State v. Ericson, 13 A.3d 777 (Me. 2011) (Rule 702 reliability and relevance indicia for expert testimony)
Boutilier v. State, 426 A.2d 876 (Me. 1981) (inadmissible expert testimony lacks probative value)
State v. Hatt, 810 A.2d 415 (Me. 2002) (expert excluded when offer of proof insufficient to show relevance)
State v. Collin, 441 A.2d 693 (Me. 1982) (expert testimony properly excluded absent record link to defendant)
State v. Tellier, 526 A.2d 941 (Me. 1987) (expert testimony too speculative is properly excluded)
State v. Cross, 732 A.2d 278 (Me. 1999) (Sixth Amendment compulsory-process limits)
State v. Williams, 462 A.2d 491 (Me. 1983) (requirements for a proper offer of proof)