Seven Chicago police officers who were put on paid desk duty Thursday could be in hot water for years. The department isn’t naming the officers but says it’s investigating them about cases tied to Ronald Watts, a sergeant who went to prison for corruption. Cook County judges have thrown out 26 drug convictions involving Watts. The exonerees say he and his crew did stuff like plant evidence and lie on the witness stand. Civil-rights attorneys say it might be too late to prosecute officers for those crimes but not for any perjury or obstruction of justice during what’s expected to be a flood of lawsuits from the exonerees. That’s how prosecutors put accused police torturer Jon Burge in prison.