zabbix API get alert from triggerids

[hvaithianathan]

Hi I need to get the list of alerts opened by a particular trigger. I use the following JSON object to get this info but it returns empty.

{
"jsonrpc": "2.0",
"method": "alert.get",
"params":{
"output": "extend",
"objectids": 13913
},
"auth": "aa94c690efe1b15cfa1d8a4e27b4bd77",
"id": 1
}
There is an alert which is opened by this particular object (trigger) but I dont see that. What am I missing?