Task: Question Answering
Input (English): Context: In 1977 , a dead author of detective stories saved the life of a nineteen-month-old baby in a most unusual way. The author was Agatha Christie, a gentle married lady and one of the most successful writers of detective stories in the world. ks5u In June 1977 , a baby girl became seriously ill in Qatar , near Sandi Arabia . Doctors were unable to find out the cause of her illness, so she was flown to London and sent to Hammersmith Hospital. A team of doctors hurried to examine the baby only to discover that they, too, were puzzled by the very unusual signs of illness. While they were having a discussion about the baby's illness, a nurse asked to speak to them. "Excuse me," said Nurse Marsha Maitland, "but I think the baby is suffering from thallium poisoning ." "What makes you think that?" Dr. Brown asked. "Thallium poisoning is very rare." "A few days ago, I was reading a novel called 'A Pale Horse' by Agatha Christie," Nurse Maitland explained. "In the book, somebody uses thallium poison, and all the signs are exactly the same as the baby' s . " "You are very careful and you may be right," another doctor said. "we'll carry out some tests and find out whether it' s thallium or not." Tests showed that the baby had indeed been poisoned by thallium. Once they knew the cause of the illness, the doctors were able to give the baby the correct treatment. She soon recovered and was sent back to Qatar. Later on it was proved that the poison might have come from an insecticide used in Qatar. 
 Question: Who first suggested the correct cause of the baby's illness?
Output (English): nurse maitland.