Seoul, South Korea ? For North Korea, the deadly sinking of a South Korean warship a month ago may end up being the perfect crime.

Investigators have yet to produce proof that North Korea engineered the ship’s demise, but analysts say even if they do, Seoul won’t risk triggering another costly war by striking back militarily.

And if there’s no evidence pointing to North Korea, its government may still quietly claim it as a victory to bolster support at home.

As South Korea honored the 46 dead sailors in an emotional farewell Thursday, the question of what struck the Cheonan remained unsolved, casting a pall over North Korea’s relationships with Seoul and Washington and calling into question the future of stalled six-nation nuclear disarmament talks.

The 1,200-ton Cheonan was on a routine patrol mission in the waters near the Koreas’ maritime border when an explosion ripped the sturdy frigate in two. Fifty-eight sailors were rescued; 46 others perished.

The South Korean military was careful early on not to cast suspicion on North Korea, even though the Yellow Sea has been the site of three bloody skirmishes between the two countries, most recently in November. One North Korean was killed in that clash, South Korea said.

Military experts laid out the possibilities: a weapon stored on board? Collision with a rock, a mine left over from the Korean War? Or was it a torpedo fired from a submarine that went undetected by the ship’s sophisticated radars?

Defectors claiming knowledge of North Korean military operations called it sabotage, describing naval squads in slow-moving submarines outfitted with torpedoes. North Korea denied involvement.

The day the ship’s damaged stern was raised from the waters, the chief investigator offered a damaging initial assessment: an underwater explosion.

The investigation still under way, the defense minister said Sunday that an outside explosion — probably created by a torpedo blast near the ship — appeared probable.