Bogota - A mother driven to desperation by poverty and abandonment is suspected of having killed her four children this week, before taking her own life, Colombian authorities said yesterday. Police said the bodies of Rosalba Sanchez de Santana and her two boys and two girls, aged between five and 11, were discovered early yesterday in their ramshackle house in a rural area about 18 miles (30 km) north of Bogota. All apparently died after swallowing a poison that Sanchez (33) is believed to have slipped into their final meal.