Can't access sprite methods while using getChildAt()

[maxpower]

Hey Guys, I'm using typescript in visual studio for web and can't access the sprite methods when using though group call getChildAt()

 

e.g this.objectsGroup.getChildAt(i).destroy();  

 

This is the error I get

Error    1    Build: Property 'destroy' does not exist on type 'DisplayObject'.

 

Not sure if i'm meant to cast this?
 

Any help would be much appreciated

class below.

 

module Test {
    export class Level1 extends Phaser.State {

        background: Phaser.Sprite;
        crossHairGroup: Phaser.Group;
        poleGroup: Phaser.Group;
        objectsGroup: Phaser.Group;
        crossHair: CrossHair;
        pole: Phaser.Sprite;
        object: Phaser.Sprite;

        create() {
 
            this.crossHairGroup = this.game.add.group();
            this.poleGroup = this.game.add.group();
            this.objectsGroup = this.game.add.group();

            this.background = this.game.add.sprite(this.game.world.centerX, this.game.world.centerY, 'background');
            this.background.anchor.setTo(0.5, 0.5);

            this.crossHair = new CrossHair(this.game, this.game.input.x, this.game.input.y, this.crossHairGroup);

            this.initializeObjects();
            this.game.input.onDown.add(this.fire, this);
        }

        fire() {
            var bullet = this.crossHair.fire();

            /* Check if bullet hits object */
            for (var i = 0; i < this.objectsGroup.length; i++) {

                if (this.checkOverlap(this.objectsGroup.getChildAt(i), bullet)) {
                    this.objectsGroup.add(this.object);

 

                    /* this line not working */
                    //this.objectsGroup.getChildAt(i).destroy();               
                    
                }
            }
        }

        checkOverlap(spriteA, spriteB) {

            var boundsA = spriteA.getBounds();
            var boundsB = spriteB.getBounds();

            return Phaser.Rectangle.intersects(boundsA, boundsB);
        }

        initializeObjects() {
            
            /* Initialize  poles and objects */
            for (var i = 0; i < 7; i++) {
                
                /* Top poles */
                this.pole = new Pole(this.game,(i * -200), 235, false);
                this.poleGroup.add(this.pole);

                /* Bottom poles */
                this.pole = new Pole(this.game,((i * 200) + 1024), 45, true);
                this.poleGroup.add(this.pole);

                /* Top objects */
                this.object = new Object(this.game,(i * -200), 300, false);
                this.objectsGroup.add(this.object);
                
                /* Bottom objects */
                this.object = new Object(this.game,((i * 200) + 1024), 100, true);
                this.objectsGroup.add(this.object);

            }

        }
    }
}

[maxpower]

Okay so casting worked fine, getChildAt() doesn't actually return a sprite.

 

 var test = <Object> this.objectsGroup.getChildAt(i);
                    test.destroy();