Five down-and-outers were bludgeoned to death between September and November, striking terror into the small homeless community who hover around Union Station. Last week, eight young men were arrested and the Colorado capital thought the trauma was over. Then, on Wednesday, two bodies were found decapitated in a weed-strewn field behind the station, and the city descended into panic.
More than 100 police officers have been combing the area for clues, taming the foliage with lawn-mowers and bringing in sniffer dogs and forensic experts to hunt for evidence. At the city's request, the Federal Bureau of Investigation has been drafted to help. Homeless men have armed themselves with knives, pipes and spikes.
One homeless man, Dave Roy, said, as he was lining up for a bed at the Denver Rescue Mission: "Somebody has something against the homeless. I don't think this is the end. I don't think it's over. This is the worst thing I have seen in 18 years on the street."
The police do not know if the murders are the work of a serial killer, part of a gang war, or the work of sick copy-cats inspired by reports of the crimes.
The arrests were a round-up of "mall rats", semi-vagrant teenagers who roam the pedestrian shopping area on Denver's 16th Street. Three were charged for one of the beating deaths. The others were accused of assault. The theory then was that a conflict was pitting the younger boys and against the older homeless population.
Now one possible lead is focussing on a gang, the Freight Train Riders of America, believed to be responsible for as many as 300 murders along rail tracks across the country. Another possibility is a serial killer.
"The deaths of seven homeless men have left our community in a state of disbelief,'' said Denver's Mayor, Wellington Webb. "We thought this was over."