The prosecution had termed the case as "very serious" and justified their arrest ahead of the court verdict.
"They are facing child abuse case and are charged with gross or repeated maltreatment of their child/children by threats, violence or other wrong, under section 219," Kurt Lir, Head of Prosecution, Oslo Police Department, said.
He said, "there were burn marks and scars on the body of the child, who has also been beaten by the belt."
Asked why the police arrested the couple -- Chandrasekhar Vallabhaneni, a software professional from Andhra Pradesh, and his wife Anupama -- before the sentencing, Lir said, it is feared that they will evade prosecution by returning to India.
"Under three circumstances i.e if we are concerned about (tampering) of the evidence or we fear they may leave the country or they might do it again, we make arrests before the sentencing," he said.
On whether the police department came across such cases often, he said, "Yes, it is quite often. And not only foreigners but Norwegians are also involved in such cases."
He also said prosecution has proposed a sentence of 15 months for the mother and 18 months for the father in the case.
Anupama's lawyer Marte Brotrome said it was wrong to keep the Indian couple in prison in Norway.
"We will appeal against it," she has said.
"They didn't hurt their children. They had some difficulties in handling the boy, but they didn't hurt him and they didn't mean to do anything wrong. They tried to get help but they did not get any help," she said.
The police arrested Chandrasekhar, nine months after the child complained to his school teachers that his parents were threatening to send him back to India for his acts.
Indian government has already indicated that it will not intervene in the legal process of that country.
"This is an issue that relates not to the government. It relates to a private citizen and to the local law of that country," External Affairs Minister Salman Khurshid has said.
Family members of the Indian couple expressed their disappointment over the verdict and sought intervention of the government.
The family members of Chandrasekhar Vallabhaneni said they will appeal in a higher court against the judgment.
"We are thoroughly disappointed with the court judgment. The Indian government has not responded on time. The judgment itself violates child rights as the two children of my uncle will not have parental guidance as long as they are in prison," Chandrasekhar's nephew Sailendra told reporters.
"We will now appeal in the higher court. We also request the Indian government to intervene," he added.