Problem obtaining a parameter from the url (the ID)

I'm trying to take the id parameter that I'm passing through the url to get the whole json from just the id but by doing console.log it tells me it's undefined but the id is passed correctly by the url only that I can not get, then I have set as I am doing:

  import { Component, OnInit } from '@angular/core';
    import { Empleado } from '../modelo-de-datos/empleados';
    import { EmpleadoServiceService } from '../servicios/empleado-service.service';
    import {Router, ActivatedRoute, Params} from '@angular/router';

    @Component({
      selector: 'app-empleados-info',
      templateUrl: './empleados-info.component.html',
      styleUrls: ['./empleados-info.component.css']
    })
    export class EmpleadosInfoComponent implements OnInit {

      private empleado: Empleado;
      activatedRoute: any;


      constructor(
        private empleadoService: EmpleadoServiceService,
        private route: ActivatedRoute
      ) { }

      ngOnInit() {
        this.getFullInfo();
      }

      getFullInfo() {
        let id: string;

        this.route.snapshot.queryParamMap.get('_id');

        console.log('ID = '+id);

        this.empleadoService.getEmpleado(id).subscribe(

          res => {
            this.empleado = res as Empleado;
            console.log(this.empleado);
          },
          error =>{
            console.log(error);
          }


        )
      }



    }

console chrome

http://localhost:3000/getEmpleado/undefined net::ERR_EMPTY_RESPONSE

I have already tried several ways to see if someone controls this well and knows what causes the undefined