Murder mystery where perp uses plant

An old professor rents a mysterious old villa, and finds a tape recorded by a previous occupant, detailing her debauched lifestyle and the events leading to her murder.

An aspiring rock band decide that the best way for them to get ahead is for one of them to die.

Landau, the young owner of "Lotus Cat Food", is struggling to keep the company alive as business is worse than expected. Landau is broke and down on his luck and can no longer afford to pay his employees. Because of this, he starts to kill one of his employees every couple of days. Gradually, more people disappear until the police become involved in the case. One of the missing persons, Frank, has an overprotective girlfriend, Tessie, who sets out in search for him. Tessie follows the leads all the way back to "Lotus Cat Food" and its sinister truths.

When the Lotus Cat Food Company finds itself in financial trouble, the owners decide to find a new, cheap source of meat -- the local graveyard. Only one problem -- soon cats develop a taste for human flesh, and tabbies are tearing out throats all over town.

A detective wonders that his sister is a murder suspect.

Set in the USA, the plot concerns Thomas Norton, a researcher in the field of lie detection, who provides his services to courts and private industry. One day he idly attaches electrodes to a plant in his office, and is surprised to find it responds with recognisable emotional reactions to the stimuli he gives it. He pursues this research, and keeps a plant wired up in his lab. When a woman who lives in his building is mysteriously murdered in his lab, the plant is the only witness to the crime.

Lieutenant Pereira is puzzled by the mysterious murder of a prostitute: it's the second time a woman has been found with her nose cut off, and a special plant known as a "goosefoot" placed beneath her corpse. Suspecting that the killer is basing his actions on the medieval board game of the Oca Brothers, Pereira asks Professor Rinaldi for help. His insight comes too late however: Tea, a young girl on a pilgrimage with a group of young offenders and their minder Leyva, is found murdered.