the property’s use proximately caused the personal injury or death. Bossley, 968 S.W.2d at 342-43. Proximate cause consists of cause-in-fact and foreseeability. Leitch v. Hornsby, 935 S.W.2d 114, 118 (Tex.1996). The test for cause-in-fact is whether the act or omission was a substantial factor in causing the injury, without which the harm would have not occurred. Doe v. Boys Clubs of Greater Dallas, Inc., 907 S.W.2d 472, 477 (Tex.1995). To establish cause in fact, or “but for” causation, a party must show that the defend was alleged, we need not reach the issue of causation. We sustain the City’s issue with respect to the negligence claim arising out of the failure to restrain Mark in the second patrol car. Conclusion We reverse the ord n v. Bossley, 968 S.W.2d 339, 343 (Tex.1998) (<HOLDING>); Archibeque v. N. Tex. State Hosp.—Wichita
holding in a medicalmalpractice case that defendant hospital and physicians failure to sufficiently monitor a suicidal patient who slipped out of restraints left the hospital and committed suicide the next day was not the proximate cause of the patients death as a matter of law holding that ttca does not waive immunity from suit for claim whose substance is that patients death was caused by hospital staffs failure to restrain patient after having learned that he was suicidal holding that claim based on failure to restrain inmate by handcuffing or shackling was allegation of nonuse of property for which ttca did not waive immunity holding that failure to lock door through which patient escaped and later drowned was nonuse of property for which ttca did not waive immunity holding that ttca did not waive immunity for claim based on failure properly to evaluate and to restrain patient who was assaulted by fellow patients after exiting unlocked door