Illinois Statutes Chapter 720. Criminal Offenses § 5/1-5. State criminal jurisdiction

(a) A person is subject to prosecution in this State for an offense which he commits, while either within or outside the State, by his own conduct or that of another for which he is legally accountable, if:

(b) An offense is committed partly within this State, if either the conduct which is an element of the offense, or the result which is such an element, occurs within the State. In a prosecution pursuant to paragraph (3) of subsection (a) of Section 9-1, the attempt or commission of a forcible felony other than second degree murder within this State is conduct which is an element of the offense for which a person is subject to prosecution in this State. In homicide, the “result” is either the physical contact which causes death, or the death itself; and if the body of a homicide victim is found within the State, the death is presumed to have occurred within the State.

(c) An offense which is based on an omission to perform a duty imposed by the law of this State is committed within the State, regardless of the location of the offender at the time of the omission.