Killing students because they are Indians is too random in order to have any effect on the Indian government.
Killing Indian students because they're related to someone or the other in India and its system requires specific targeting information. It also assumes that the we are past the saam and daam stages and are at the dand stage against the specific individuals.
Related to the above, all states work from the adage, once is an accident, twice is a coincidence, third time is a result of deliberate enemy action. Do we actually know about the background of the victims in order to reach the conclusion that it's happening in order to excercise control over India.
Third, an international student is a customer. If the host nation is deliberately killing the customer, or is looking the other way. Then it's bad for business.
We also don't know how many University students are murdered in the US on an annual basis.
It's entirely possible that of all the murders of students. Statistically, the killing of Indian students is no different from other ethnic groups. But we know about this because they are Indians and the Indian media is highlighting these murders.